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133-414: Commercial flights are often categorized into long-, medium- or short-haul by commercial airlines based on flight length, although there is no international standard definition. The related term flight time is defined by ICAO (International Civil Aviation Organization) as "The total time from the moment an aeroplane first moves for the purpose of taking off until the moment it finally comes to rest at

266-473: A Comet 4, and Pan Am followed on 26 October with a Boeing 707 service between New York and Paris. The next big boost for the airlines would come in the 1970s, when the Boeing 747 , McDonnell Douglas DC-10 , and Lockheed L-1011 inaugurated widebody ("jumbo jet") service, which is still the standard in international travel. The Tupolev Tu-144 and its Western counterpart, Concorde , made supersonic travel

399-624: A biological attack. El Niño-Southern Oscillation (ENSO) influences the average location of upper-level jet streams, and leads to cyclical variations in precipitation and temperature across North America, as well as affecting tropical cyclone development across the eastern Pacific and Atlantic basins. Combined with the Pacific Decadal Oscillation , ENSO can also impact cold season rainfall in Europe. Changes in ENSO also change

532-482: A commercial airliner. Scientists are investigating ways to harness the wind energy within the jet stream. According to one estimate of the potential wind energy in the jet stream, only one percent would be needed to meet the world's current energy needs. In the late 2000s it was estimated that the required technology would reportedly take 10–20 years to develop. There are two major but divergent scientific articles about jet stream power. Archer & Caldeira claim that

665-430: A crusade to create an air network that would link America to the world, and he achieved this goal through his airline, Pan Am , with a fleet of flying boats that linked Los Angeles to Shanghai and Boston to London . Pan Am and Northwest Airways (which began flights to Canada in the 1920s) were the only U.S. airlines to go international before the 1940s. With the introduction of the Boeing 247 and Douglas DC-3 in

798-555: A data set collected from 35 182 weather stations worldwide, including 9116 whose records go beyond 50 years, found a sharp decrease in northern midlatitude cold waves since the 1980s. Moreover, a range of long-term observational data collected during the 2010s and published in 2020 suggests that the intensification of Arctic amplification since the early 2010s was not linked to significant changes on mid-latitude atmospheric patterns. State-of-the-art modelling research of PAMIP (Polar Amplification Model Intercomparison Project) improved upon

931-449: A downturn in the nation's economy occurred. New start-ups entered during the downturn, during which time they found aircraft and funding, contracted hangar and maintenance services, trained new employees, and recruited laid-off staff from other airlines. Major airlines dominated their routes through aggressive pricing and additional capacity offerings, often swamping new start-ups. In the place of high barriers to entry imposed by regulation,

1064-575: A gift from the taxpayers. (Passenger carriers operating scheduled service received approximately $ 4 billion, subject to tax.) In addition, the ATSB approved loan guarantees to six airlines totaling approximately $ 1.6 billion. Data from the U.S. Treasury Department show that the government recouped the $ 1.6 billion and a profit of $ 339 million from the fees, interest and purchase of discounted airline stock associated with loan guarantees. The three largest major carriers and Southwest Airlines control 70% of

1197-454: A great-circle route extending northward towards the Arctic region. The apparent curve of the route is a result of distortion when plotted onto a conventional map projection and makes the route appear to be longer than it really is. Stretching a string between North America and Japan on a globe will demonstrate why this really is the shortest route despite appearances. The actual flight length

1330-559: A lack of energy from the Sun entering during the polar night . There are wind maxima at lower levels of the atmosphere that are also referred to as jets. A barrier jet in the low levels forms just upstream of mountain chains, with the mountains forcing the jet to be oriented parallel to the mountains. The mountain barrier increases the strength of the low level wind by 45 percent. In the North American Great Plains

1463-461: A major international carrier. In 1933, Aéropostale went bankrupt , was nationalized and merged into Air France . Although Germany lacked colonies, it also began expanding its services globally. In 1931, the airship Graf Zeppelin began offering regular scheduled passenger service between Germany and South America, usually every two weeks, which continued until 1937. In 1936, the airship Hindenburg entered passenger service and successfully crossed

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1596-611: A newly created Air Transportation Stabilization Board (ATSB). The applications to DOT for reimbursements were subjected to rigorous multi-year reviews not only by DOT program personnel but also by the Government Accountability Office and the DOT Inspector General. Ultimately, the federal government provided $ 4.6 billion in one-time, subject-to-income-tax cash payments to 427 U.S. air carriers, with no provision for repayment, essentially

1729-444: A non-stop flight between Papeete and Paris-Charles de Gaulle , using a Boeing 787-9 and covering 15,715 km (9,765 mi; 8,485 nmi). in a scheduled time of 16 hours and 20 minutes. As of 2023, it continues to hold the record for the longest ever scheduled commercial nonstop flight (by great circle distance) as well as the world's longest domestic flight . As of November 9, 2020, Singapore Airlines Flights 23 and 24

1862-462: A potential hazard to aircraft passenger safety, is often found in a jet stream's vicinity, but it does not create a substantial alteration of flight times. The first indications of this phenomenon came from American professor Elias Loomis (1811–1889), when he proposed the hypothesis of a powerful air current in the upper air blowing west to east across the United States as an explanation for

1995-552: A proving flight across the English Channel , despite a lack of support from the British government. Flown by Lt. H Shaw in an Airco DH.9 between RAF Hendon and Paris – Le Bourget Airport , the flight took 2 hours and 30 minutes at £21 per passenger. On August 25, 1919, the company used DH.16s to pioneer a regular service from Hounslow Heath Aerodrome to Paris's Le Bourget , the first regular international service in

2128-547: A reality. Concorde first flew in 1969 and operated through 2003. In 1972, Airbus began producing Europe's most commercially successful line of airliners to date. The added efficiencies for these aircraft were often not in speed, but in passenger capacity, payload, and range. Airbus also features modern electronic cockpits that were common across their aircraft to enable pilots to fly multiple models with minimal cross-training. The 1978 U.S. airline industry deregulation lowered federally controlled barriers for new airlines just as

2261-500: A result of the terrorist attacks. This resulted in the first government bailout of the 21st century. Between 2000 and 2005 US airlines lost $ 30 billion with wage cuts of over $ 15 billion and 100,000 employees laid off. In recognition of the essential national economic role of a healthy aviation system, Congress authorized partial compensation of up to $ 5 billion in cash subject to review by the U.S. Department of Transportation and up to $ 10 billion in loan guarantees subject to review by

2394-755: A scale of 1,000 to 4,000 kilometres (600–2,500 mi) long, that move along through the flow pattern around large scale, or longwave, "ridges" and "troughs" within Rossby waves. Jet streams can split into two when they encounter an upper-level low, that diverts a portion of the jet stream under its base, while the remainder of the jet moves by to its north. The wind speeds are greatest where temperature differences between air masses are greatest, and often exceed 92 km/h (50 kn; 57 mph). Speeds of 400 km/h (220 kn; 250 mph) have been measured. The jet stream moves from West to East bringing changes of weather. Meteorologists now understand that

2527-467: A serious competitive threat to the legacy carriers. However, of these, ATA and Skybus have since ceased operations. Increasingly since 1978, US airlines have been reincorporated and spun off by newly created and internally led management companies, and thus becoming nothing more than operating units and subsidiaries with limited financially decisive control. Among some of these holding companies and parent companies which are relatively well known, are

2660-510: A sharp contrast between high temperatures over land and lower temperatures over the sea and play an important role in coastal weather, giving rise to strong coast parallel winds. Most coastal jets are associated with the oceanic high-pressure systems and thermal low over land. These jets are mainly located along cold eastern boundary marine currents, in upwelling regions offshore California, Peru–Chile, Benguela, Portugal, Canary and West Australia, and offshore Yemen–Oman. A valley exit jet

2793-471: A southerly low-level jet helps fuel overnight thunderstorm activity during the warm season, normally in the form of mesoscale convective systems which form during the overnight hours. A similar phenomenon develops across Australia, which pulls moisture poleward from the Coral Sea towards cut-off lows which form mainly across southwestern portions of the continent . Coastal low-level jets are related to

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2926-431: A subtropical jet. The northern hemisphere polar jet flows over the middle to northern latitudes of North America , Europe , and Asia and their intervening oceans , while the southern hemisphere polar jet mostly circles Antarctica , both all year round. Jet streams are the product of two factors: the atmospheric heating by solar radiation that produces the large-scale polar, Ferrel, and Hadley circulation cells, and

3059-609: A type of fire balloon , was designed as a cheap weapon intended to make use of the jet stream over the Pacific Ocean to reach the west coast of Canada and the United States . Relatively ineffective as weapons, they were used in one of the few attacks on North America during World War II , causing six deaths and a small amount of damage. American scientists studying the balloons thought the Japanese might be preparing

3192-503: Is a big part of the amplification story—a big reason the Arctic is warming faster than anywhere else." In a 2017 study conducted by climatologist Judah Cohen and several of his research associates, Cohen wrote that "[the] shift in polar vortex states can account for most of the recent winter cooling trends over Eurasian midlatitudes". A 2018 paper from Vavrus and others linked Arctic amplification to more persistent hot-dry extremes during

3325-488: Is a company that provides air transport services for traveling passengers or freight . Airlines use aircraft to supply these services and may form partnerships or alliances with other airlines for codeshare agreements , in which they both offer and operate the same flight. Generally, airline companies are recognized with an air operating certificate or license issued by a governmental aviation body. Airlines may be scheduled or charter operators. The first airline

3458-504: Is a strong, down-valley, elevated air current that emerges above the intersection of the valley and its adjacent plain. These winds frequently reach speeds of up to 20 m/s (72 km/h; 45 mph) at heights of 40–200 m (130–660 ft) above the ground. Surface winds below the jet tend to be substantially weaker, even when they are strong enough to sway vegetation. Valley exit jets are likely to be found in valley regions that exhibit diurnal mountain wind systems, such as those of

3591-408: Is closely associated with Jennifer Francis , who had first proposed it in a 2012 paper co-authored by Stephen J. Vavrus. While some paleoclimate reconstructions have suggested that the polar vortex becomes more variable and causes more unstable weather during periods of warming back in 1997, this was contradicted by climate modelling, with PMIP2 simulations finding in 2010 that the Arctic oscillation

3724-514: Is greater than average across the southern Rockies and Sierra Nevada mountain range, and is well below normal across the Upper Midwest and Great Lakes states. The northern tier of the lower 48 exhibits above normal temperatures during the fall and winter, while the Gulf coast experiences below normal temperatures during the winter season. The subtropical jet stream across the deep tropics of

3857-413: Is most significant during double Rossby wave breaking events. At high altitudes, lack of friction allows air to respond freely to the steep pressure gradient with low pressure at high altitude over the pole. This results in the formation of planetary wind circulations that experience a strong Coriolis deflection and thus can be considered 'quasi-geostrophic'. The polar front jet stream is closely linked to

3990-437: Is proportional to the horizontal temperature gradient. If two air masses in the northern hemisphere, one cold and dense to the north and the other hot and less dense to the south, are separated by a vertical boundary and that boundary should be removed, the difference in densities will result in the cold air mass slipping under the hotter and less dense air mass. The Coriolis effect will then cause poleward-moving mass to deviate to

4123-779: Is responsible for dust emission from the Bodélé Depression , the world's most important single source of dust emission. The Somali Jet , which forms off the East African coast is an important component of the global Hadley circulation, and supplies water vapour to the Asian Monsoon . Easterly low-level jets forming in valleys within the East African Rift System help account for the low rainfall in East Africa and support high rainfall in

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4256-463: Is strongest on the cold air side of the jet, next to and just under the axis of the jet. Clear-air turbulence can cause aircraft to plunge and so present a passenger safety hazard that has caused fatal accidents, such as the death of one passenger on United Airlines Flight 826 . Unusual wind speed in the jet stream in late February 2024 pushed commercial jets to excess of 800 mph (1,300 km/h; 700 kn) in their flight path, unheard of for

4389-540: Is symmetric with respect to longitude. Tropical air rises to the tropopause, and moves poleward before sinking; this is the Hadley cell circulation. As it does so it tends to conserve angular momentum, since friction with the ground is slight. Air masses that begin moving poleward are deflected eastward by the Coriolis force (true for either hemisphere), which for poleward moving air implies an increased westerly component of

4522-400: Is the length of the track flown across the ground in practice, which is usually longer than the ideal great-circle and is influenced by a number of factors such as the need to avoid bad weather, wind direction and speed, fuel economy, navigational restrictions and other requirements. In the example, easterly flights from Japan to North America are shown taking a longer, more southerly, route than

4655-547: Is the shortest commercial flight in the world, covering 2.8 km (1.7 mi) in two minutes scheduled flight time including taxiing. The world's longest ever commercial flight was Air Tahiti Nui Flight TN64 in early 2020. Due to the COVID-19 pandemic and the impossibility of transit in the United States through Los Angeles International Airport , Air Tahiti Nui scheduled and operated in March and April 2020 Flight TN64 as

4788-401: Is the world's longest active commercial flight between Singapore and New York–JFK , covering 15,349 km (9,537 mi; 8,288 nmi) in around 18 hours and 40 minutes, operated by an Airbus A350-900ULR . The shortest distance between two geographical points is the great-circle distance . In the example (right), the aircraft travelling westward from North America to Japan is following

4921-443: The 2010 Pakistan floods , and suggested that these patterns were all connected to Arctic amplification. Further work from Francis and Vavrus that year suggested that amplified Arctic warming is observed as stronger in lower atmospheric areas because the expanding process of warmer air increases pressure levels which decreases poleward geopotential height gradients. As these gradients are the reason that cause west to east winds through

5054-699: The Congo Basin rainforest. The formation of the thermal low over northern Africa leads to a low-level westerly jet stream from June into October, which provides the moist inflow to the West African monsoon . While not technically a low-level jet, the mid-level African easterly jet (at 3000–4000 m above the surface) is also an important climate feature in Africa. It occurs during the Northern Hemisphere summer between 10°N and 20°N above in

5187-571: The Farman F.60 Goliath plane flew scheduled services from Toussus-le-Noble to Kenley , near Croydon , England. Another early French airline was the Compagnie des Messageries Aériennes , established in 1919 by Louis-Charles Breguet , offering a mail and freight service between Le Bourget Airport , Paris and Lesquin Airport , Lille . The first German airline to use heavier than air aircraft

5320-608: The February 2021 North American cold wave . Another 2021 study identified a connection between the Arctic sea ice loss and the increased size of wildfires in the Western United States . However, because the specific observations are considered short-term observations, there is considerable uncertainty in the conclusions. Climatology observations require several decades to definitively distinguish various forms of natural variability from climate trends. This point

5453-654: The Ford Motor Company bought out the Stout Aircraft Company and began construction of the all-metal Ford Trimotor , which became the first successful American airliner. With a 12-passenger capacity, the Trimotor made passenger service potentially profitable. Air service was seen as a supplement to rail service in the American transportation network. At the same time, Juan Trippe began

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5586-694: The Great Plains . During the Dust Bowl, the jet stream weakened and changed course traveling farther south than normal. This starved the Great Plains and other areas of the Midwest of rainfall, causing extraordinary drought conditions. Since the early 2000s, climate models have consistently identified that global warming will gradually push jet streams poleward. In 2008, this was confirmed by observational evidence, which proved that from 1979 to 2001,

5719-520: The Luxembourg to Bucharest route operated by Luxair , the scheduled flight length remains constant while the flight duration varies depending on aircraft used. On Thursday mornings, Luxair operates a DHC-8 turboprop with a scheduled duration of approximately 3 hours, while on Saturday mornings, Luxair's use of an Embraer 190 jet reduces the scheduled duration of the flight down to approximately 2 hours 20 minutes. Airline An airline

5852-654: The Northern Hemisphere is enhanced due to increased convection in the equatorial Pacific, which decreases tropical cyclogenesis within the Atlantic tropics below what is normal, and increases tropical cyclone activity across the eastern Pacific. In the Southern Hemisphere, the subtropical jet stream is displaced equatorward, or north, of its normal position, which diverts frontal systems and thunderstorm complexes from reaching central portions of

5985-700: The Tupolev Tu-104 . Deregulation of the European Union airspace in the early 1990s has had substantial effect on the structure of the industry there. The shift towards 'budget' airlines on shorter routes has been significant. Airlines such as EasyJet and Ryanair have often grown at the expense of the traditional national airlines. There has also been a trend for these national airlines themselves to be privatized such as has occurred for Aer Lingus and British Airways . Other national airlines, including Italy's Alitalia , suffered – particularly with

6118-652: The UAL Corporation , along with the AMR Corporation , among a long list of airline holding companies sometime recognized worldwide. Less recognized are the private-equity firms which often seize managerial, financial, and board of directors control of distressed airline companies by temporarily investing large sums of capital in air carriers, to rescheme an airlines assets into a profitable organization or liquidating an air carrier of their profitable and worthwhile routes and business operations. Thus

6251-776: The United States Army Air Service . Private operators were the first to fly the mail but due to numerous accidents the US Army was tasked with mail delivery. During the Army's involvement they proved to be too unreliable and lost their air mail duties. By the mid-1920s, the Postal Service had developed its own air mail network, based on a transcontinental backbone between New York City and San Francisco . To supplement this service, they offered twelve contracts for spur routes to independent bidders. Some of

6384-454: The frontogenesis process in midlatitudes, as the acceleration/deceleration of the air flow induces areas of low/high pressure respectively, which link to the formation of cyclones and anticyclones along the polar front in a relatively narrow region. A second factor which contributes to a concentrated jet is more applicable to the subtropical jet which forms at the poleward limit of the tropical Hadley cell , and to first order this circulation

6517-564: The 1930s, the U.S. airline industry was generally profitable, even during the Great Depression . This trend continued until the beginning of World War II . World War II, like World War I, brought new life to the airline industry. Many airlines in the Allied countries were flush from lease contracts to the military, and foresaw a future explosive demand for civil air transport, for both passengers and cargo. They were eager to invest in

6650-495: The 2010 findings of PMIP2; it found that sea ice decline would weaken the jet stream and increase the probability of atmospheric blocking, but the connection was very minor, and typically insignificant next to interannual variability. In 2022, a follow-up study found that while the PAMIP average had likely underestimated the weakening caused by sea ice decline by 1.2 to 3 times, even the corrected connection still amounts to only 10% of

6783-542: The Arctic to heat up faster than other parts of the globe, in what is known as the Arctic amplification . In 2021–2022, it was found that since 1979, the warming within the Arctic Circle has been nearly four times faster than the global average, and some hotspots in the Barents Sea area warmed up to seven times faster than the global average. While the Arctic remains one of the coldest places on Earth today,

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6916-553: The Atlantic 36 times before crashing at Lakehurst, New Jersey, on 6 May 1937. In 1938, a weekly air service from Berlin to Kabul , Afghanistan , started operating. From February 1934 until World War II began in 1939, Deutsche Lufthansa operated an airmail service from Stuttgart , Germany via Spain , the Canary Islands and West Africa to Natal in Brazil . This was the first time an airline flew across an ocean. By

7049-532: The Earth's jet streams could generate a total power of 1700 terawatts (TW) and that the climatic impact of harnessing this amount would be negligible. However, Miller, Gans, & Kleidon claim that the jet streams could generate a total power of only 7.5 TW and that the climatic impact would be catastrophic. Near the end of World War II , from late 1944 until early 1945, the Japanese Fu-Go balloon bomb ,

7182-563: The East, while equatorward-moving mass will deviate toward the west. The general trend in the atmosphere is for temperatures to decrease in the poleward direction. As a result, winds develop an eastward component and that component grows with altitude. Therefore, the strong eastward moving jet streams are in part a simple consequence of the fact that the Equator is warmer than the north and south poles. The thermal wind relation does not explain why

7315-613: The North Atlantic, the jet stream is stronger than normal, which directs stronger systems with increased precipitation towards Europe. Evidence suggests the jet stream was at least partly responsible for the widespread drought conditions during the 1930s Dust Bowl in the Midwest United States. Normally, the jet stream flows east over the Gulf of Mexico and turns northward pulling up moisture and dumping rain onto

7448-412: The Northern Hemisphere summer, easterly jets can form in tropical regions, typically where dry air encounters more humid air at high altitudes. Low-level jets also are typical of various regions such as the central United States. There are also jet streams in the thermosphere . Meteorologists use the location of some of the jet streams as an aid in weather forecasting . The main commercial relevance of

7581-451: The U.S. National Oceanic and Atmospheric Administration (NOAA) cited vertical wind shear as evidenced in the photo. On Earth, the northern polar jet stream is the most important one for aviation and weather forecasting, as it is much stronger and at a much lower altitude than the subtropical jet streams and also covers many countries in the Northern Hemisphere , while the southern polar jet stream mostly circles Antarctica and sometimes

7714-493: The U.S. passenger market. Although Philippine Airlines (PAL) was officially founded on February 26, 1941, its license to operate as an airliner was derived from merged Philippine Aerial Taxi Company (PATCO) established by mining magnate Emmanuel N. Bachrach on 3 December 1930, making it Asia's oldest scheduled carrier still in operation. Commercial air service commenced three weeks later from Manila to Baguio , making it Asia's first airline route. Bachrach's death in 1937 paved

7847-744: The US to the UK. Similarly in 1944 a team of American meteorologists in Guam , including Reid Bryson , had enough observations to forecast very high west winds that would slow bombers raiding Japan. Polar jet streams are typically located near the 250 hPa (about 1/4 atmosphere) pressure level, or seven to twelve kilometres (23,000 to 39,000 ft) above sea level , while the weaker subtropical jet streams are much higher, between 10 and 16 kilometres (33,000 and 52,000 ft). Jet streams wander laterally dramatically, and change in altitude. The jet streams form near breaks in

7980-529: The United States until its closure in 2008. Following World War I , the United States found itself swamped with aviators. Many decided to take their war-surplus aircraft on barnstorming campaigns, performing aerobatic maneuvers to woo crowds. In 1918, the United States Postal Service won the financial backing of Congress to begin experimenting with air mail service, initially using Curtiss Jenny aircraft that had been procured by

8113-490: The action of the Coriolis force acting on those moving masses. The Coriolis force is caused by the planet's rotation on its axis. On other planets, internal heat rather than solar heating drives their jet streams. The polar jet stream forms near the interface of the polar and Ferrel circulation cells; the subtropical jet forms near the boundary of the Ferrel and Hadley circulation cells. Other jet streams also exist. During

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8246-485: The air. Oishi's work largely went unnoticed outside Japan because it was published in Esperanto , though chronologically he has to be credited for the scientific discovery of jet streams. American pilot Wiley Post (1898–1935), the first man to fly around the world solo in 1933, is often given some credit for discovery of jet streams. Post invented a pressurized suit that let him fly above 6,200 metres (20,300 ft). In

8379-467: The average domestic ticket price has dropped by 40%. So has airline employee pay. By incurring massive losses, the airlines of the USA now rely upon a scourge of cyclical Chapter 11 bankruptcy proceedings to continue doing business. America West Airlines (which has since merged with US Airways) remained a significant survivor from this new entrant era, as dozens, even hundreds, have gone under. In many ways,

8512-433: The aviation term of "Flight Haul Type", such as "short-haul" or "long-haul". Flight haul types can be defined using either flight distance or flight time. David W. Wragg classifies air services as medium-haul being between 1,600–4,000 km; 900–2,200 nmi; short-haul as being shorter and long-haul as being longer. David Crocker defines short-haul flights as shorter than 1,000 km (540 nmi), and long-haul as

8645-488: The behaviour of major storms. After the 1883 eruption of the Krakatoa volcano , weather watchers tracked and mapped the effects on the sky over several years. They labelled the phenomenon the "equatorial smoke stream". In the 1920s Japanese meteorologist Wasaburo Oishi detected the jet stream from a site near Mount Fuji . He tracked pilot balloons ("pibals"), used to measure wind speed and direction, as they rose in

8778-499: The biggest winner in the deregulated environment was the air passenger. Although not exclusively attributable to deregulation, indeed the U.S. witnessed an explosive growth in demand for air travel. Many millions who had never or rarely flown before became regular fliers, even joining frequent flyer loyalty programs and receiving free flights and other benefits from their flying. New services and higher frequencies meant that business fliers could fly to another city, do business, and return

8911-406: The carriers that won these routes would, through time and mergers, evolve into Pan Am , Delta Air Lines , Braniff Airways , American Airlines , United Airlines (originally a division of Boeing ), Trans World Airlines , Northwest Airlines , and Eastern Air Lines . Service during the early 1920s was sporadic: most airlines at the time were focused on carrying bags of mail . In 1925, however,

9044-634: The continent. Across North America during La Niña , increased precipitation is diverted into the Pacific Northwest due to a more northerly storm track and jet stream. The storm track shifts far enough northward to bring wetter than normal conditions (in the form of increased snowfall) to the Midwestern states, as well as hot and dry summers. Snowfall is above normal across the Pacific Northwest and western Great Lakes. Across

9177-483: The country's flagship carrier to this day, on 17 May 1933. Germany's Deutsche Lufthansa was created in 1926 by merger of two airlines, one of them Junkers Luftverkehr . Lufthansa, due to the Junkers heritage and unlike most other airlines at the time, became a major investor in airlines outside of Europe, providing capital to Varig and Avianca. German airliners built by Junkers , Dornier , and Fokker were among

9310-469: The direction of the remainder of the jet. The strongest jet streams are the polar jets around the polar vortices , at 9–12 km (5.6–7.5 mi; 30,000–39,000 ft) above sea level, and the higher altitude and somewhat weaker subtropical jets at 10–16 km (6.2–9.9 mi; 33,000–52,000 ft). The Northern Hemisphere and the Southern Hemisphere each have a polar jet and

9443-467: The domestic industry operates over 10,000 daily departures nationwide. Toward the end of the century, a new style of low cost airline emerged, offering a no-frills product at a lower price. Southwest Airlines , JetBlue , AirTran Airways , Skybus Airlines and other low-cost carriers began to represent a serious challenge to the so-called "legacy airlines", as did their low-cost counterparts in many other countries. Their commercial viability represented

9576-518: The dry mountain ranges of the US. Deep valleys that terminate abruptly at a plain are more impacted by these factors than are those that gradually become shallower as downvalley distance increases. There are several important low-level jets in Africa. Numerous low-level jets form in the Sahara , and are important for the raising of dust off the desert surface. This includes a low-level jet in Chad , which

9709-506: The end of the 1930s Aeroflot had become the world's largest airline, employing more than 4,000 pilots and 60,000 other service personnel and operating around 3,000 aircraft (of which 75% were considered obsolete by its own standards). During the Soviet era Aeroflot was synonymous with Russian civil aviation, as it was the only air carrier. It became the first airline in the world to operate sustained regular jet services on 15 September 1956 with

9842-477: The end of the flight", and is referred to colloquially as "blocks to blocks" or " chocks to chocks" time. In commercial aviation, this means the time from pushing back at the departure gate to arriving at the destination gate. Flight time is measured in hours and minutes as it is independent of geographic distance travelled. Flight time can be affected by many things such as wind, traffic, taxiing time, and aircraft used. A flight's length can also be described using

9975-618: The first flagships of the Jet Age in the West, while the Eastern bloc had Tupolev Tu-104 and Tupolev Tu-124 in the fleets of state-owned carriers such as Czechoslovak ČSA , Soviet Aeroflot and East-German Interflug . The Vickers Viscount and Lockheed L-188 Electra inaugurated turboprop transport. On 4 October 1958, British Overseas Airways Corporation started transatlantic flights between London Heathrow and New York Idlewild with

10108-520: The flight, it also nets fuel savings for the airline industry. Within North America, the time needed to fly east across the continent can be decreased by about 30 minutes if an airplane can fly with the jet stream, or increased by more than that amount if it must fly west against it. Associated with jet streams is a phenomenon known as clear-air turbulence (CAT), caused by vertical and horizontal wind shear caused by jet streams. The CAT

10241-407: The jet stream's natural variability. Additionally, a 2021 study found that while jet streams had indeed slowly moved polewards since 1960 as was predicted by models, they did not weaken, in spite of a small increase in waviness. A 2022 re-analysis of the aircraft observational data collected over 2002–2020 suggested that the North Atlantic jet stream had actually strengthened. Finally, a 2021 study

10374-460: The jet streams is in air travel, as flight time can be dramatically affected by either flying with the flow or against. Often, airlines work to fly 'with' the jet stream to obtain significant fuel cost and time savings. Dynamic North Atlantic Tracks are one example of how airlines and air traffic control work together to accommodate the jet stream and winds aloft that results in the maximum benefit for airlines and other users. Clear-air turbulence ,

10507-410: The jet typically has a meandering shape, and these meanders themselves propagate eastward, at lower speeds than that of the actual wind within the flow. Each large meander, or wave, within the jet stream is known as a Rossby wave (planetary wave). Rossby waves are caused by changes in the Coriolis effect with latitude. Shortwave troughs , are smaller scale waves superimposed on the Rossby waves, with

10640-513: The last 50 years of the airline industry have varied from reasonably profitable, to devastatingly depressed. As the first major market to deregulate the industry in 1978, U.S. airlines have experienced more turbulence than almost any other country or region. In fact, no U.S. legacy carrier survived bankruptcy-free. Among the outspoken critics of deregulation, former CEO of American Airlines, Robert Crandall has publicly stated: "Chapter 11 bankruptcy protection filing shows airline industry deregulation

10773-532: The location of the jet stream over South America, which partially affects precipitation distribution over the continent. During El Niño events, increased precipitation is expected in California due to a more southerly, zonal, storm track. During the Niño portion of ENSO, increased precipitation falls along the Gulf coast and Southeast due to a stronger than normal, and more southerly, polar jet stream. Snowfall

10906-405: The major airlines implemented an equally high barrier called loss leader pricing. In this strategy an already established and dominant airline stomps out its competition by lowering airfares on specific routes, below the cost of operating on it, choking out any chance a start-up airline may have. The industry side effect is an overall drop in revenue and service quality. Since deregulation in 1978

11039-547: The merger of Instone Air Line Company , British Marine Air Navigation , Daimler Airway and Handley Page Transport , to allow British airlines to compete with stiff competition from French and German airlines that were enjoying heavy government subsidies. The airline was a pioneer in surveying and opening up air routes across the world to serve far-flung parts of the British Empire and to enhance trade and integration. The first new airliner ordered by Imperial Airways,

11172-513: The merger. PAL restarted service on 15 March 1941, with a single Beech Model 18 NPC-54 aircraft, which started its daily services between Manila (from Nielson Field ) and Baguio , later to expand with larger aircraft such as the DC-3 and Vickers Viscount. Cathay Pacific was one of the first airlines to be launched among the other Asian countries in 1946 along with Asiana Airlines , which later joined in 1988. The license to operate as an airliner

11305-462: The mid-1980s. Since the 1980s, there has been a trend of major airline mergers and the formation of airline alliances. The largest alliances are Star Alliance , SkyTeam and Oneworld . Airline alliances coordinate their passenger service programs (such as lounges and frequent-flyer programs ), offer special interline tickets and often engage in extensive codesharing (sometimes systemwide). DELAG , Deutsche Luftschiffahrts-Aktiengesellschaft I

11438-445: The midlatitude summers, as well as the midlatitude winter continental cooling. Another 2017 paper estimated that when the Arctic experiences anomalous warming, primary production in North America goes down by between 1% and 4% on average, with some states suffering up to 20% losses. A 2021 study found that a stratospheric polar vortex disruption is linked with extreme cold winter weather across parts of Asia and North America, including

11571-490: The modelling results but fit the Francis-Vavrus hypothesis. Additionally, a 2013 study noted that the then-current CMIP5 tended to strongly underestimate winter blocking trends, and other 2012 research had suggested a connection between declining Arctic sea ice and heavy snowfall during midlatitude winters. In 2013, further research from Francis connected reductions in the Arctic sea ice to extreme summer weather in

11704-492: The most advanced in the world at the time. In 1926, Alan Cobham surveyed a flight route from the UK to Cape Town , South Africa , following this up with another proving flight to Melbourne , Australia . Other routes to British India and the Far East were also charted and demonstrated at this time. Regular services to Cairo and Basra began in 1927 and were extended to Karachi in 1929. The London- Australia service

11837-657: The newly emerging flagships of air travel such as the Boeing Stratocruiser , Lockheed Constellation , and Douglas DC-6 . Most of these new aircraft were based on American bombers such as the B-29 , which had spearheaded research into new technologies such as pressurization . Most offered increased efficiency from both added speed and greater payload. In the 1950s, the De Havilland Comet , Boeing 707 , Douglas DC-8 , and Sud Aviation Caravelle became

11970-415: The northern jet stream moved northward at an average rate of 2.01 kilometres (1.25 mi) per year, with a similar trend in the Southern Hemisphere jet stream. Climate scientists have hypothesized that the jet stream will also gradually weaken as a result of global warming . Trends such as Arctic sea ice decline , reduced snow cover, evapotranspiration patterns, and other weather anomalies have caused

12103-624: The northern mid-latitudes, while other research from that year identified potential linkages between Arctic sea ice trends and more extreme rainfall in the European summer. At the time, it was also suggested that this connection between Arctic amplification and jet stream patterns was involved in the formation of Hurricane Sandy and played a role in the Early 2014 North American cold wave . In 2015, Francis' next study concluded that highly amplified jet-stream patterns are occurring more frequently in

12236-893: The opposite. Flight Haul Type terms are sometimes used when referring to commercial aircraft. Some commercial carriers choose to refer to their aircraft using flight haul type terms, for example: While they are capable of flying further, long-haul capable wide-bodies are often used on shorter trips. In 2017 - 40% of A350 routes were shorter than 2,000 nmi (2,300 mi; 3,700 km), 50% of A380 flights fell within 2,000–4,000 nmi (2,300–4,600 mi; 3,700–7,400 km), 70% of 777-200ER routes were shorter than 4,000 nmi (4,600 mi; 7,400 km), 80% of 787-9s routes were shorter than 5,000 nmi (5,800 mi; 9,300 km), 70% of 777-200LRs flights were shorter than 6,000 nmi (6,900 mi; 11,000 km). The Westray to Papa Westray flight in Orkney , operated by Loganair ,

12369-411: The passenger cabins were often spacious with luxurious interiors – over speed and efficiency. The relatively basic navigational capabilities of pilots at the time also meant that delays due to the weather were commonplace. By the early 1920s, small airlines were struggling to compete, and there was a movement towards increased rationalization and consolidation. In 1924, Imperial Airways was formed from

12502-435: The past two decades. Hence, continued heat-trapping emissions favour increased formation of extreme events caused by prolonged weather conditions. Studies published in 2017 and 2018 identified stalling patterns of Rossby waves in the northern hemisphere jet stream as the culprit behind other almost stationary extreme weather events, such as the 2018 European heatwave , the 2003 European heat wave , 2010 Russian heat wave or

12635-527: The path of jet streams affects cyclonic storm systems at lower levels in the atmosphere, and so knowledge of their course has become an important part of weather forecasting. For example, in 2007 and 2012, Britain experienced severe flooding as a result of the polar jet staying south for the summer. In general, winds are strongest immediately under the tropopause (except locally, during tornadoes , tropical cyclones or other anomalous situations). If two air masses of different temperatures or densities meet,

12768-491: The planetary radius, holding all other parameters fixed, the number of jet streams decreases. The subtropical jet stream rounding the base of the mid-oceanic upper trough is thought to be one of the causes most of the Hawaiian Islands have been resistant to the long list of Hawaii hurricanes that have approached. For example, when Hurricane Flossie (2007) approached and dissipated just before reaching landfall,

12901-644: The rapid increase of oil prices in early 2008. Finnair , the largest airline of Finland , had no fatal or hull-loss accidents since 1963, and is recognized for its safety. Tony Jannus conducted the United States' first scheduled commercial airline flight on January 1, 1914, for the St. Petersburg-Tampa Airboat Line . The 23-minute flight traveled between St. Petersburg, Florida and Tampa, Florida , passing some 50 feet (15 m) above Tampa Bay in Jannus' Benoist XIV wood and muslin biplane flying boat. His passenger

13034-644: The regional market of Asian airline industry India was also one of the first countries to embrace civil aviation. One of the first Asian airline companies was Air India , which was founded as Tata Airlines in 1932, a division of Tata Sons Ltd. (now Tata Group ). The airline was founded by India's leading industrialist, JRD Tata . On 15 October 1932, J. R. D. Tata himself flew a single engined De Havilland Puss Moth carrying air mail (postal mail of Imperial Airways ) from Karachi to Bombay via Ahmedabad . The aircraft continued to Madras via Bellary piloted by Royal Air Force pilot Nevill Vintcent . Tata Airlines

13167-422: The resulting pressure difference caused by the density difference (which ultimately causes wind) is highest within the transition zone. The wind does not flow directly from the hot to the cold area, but is deflected by the Coriolis effect and flows along the boundary of the two air masses. All these facts are consequences of the thermal wind relation. The balance of forces acting on an atmospheric air parcel in

13300-399: The same day, from almost any point in the country. Air travel's advantages put long-distance intercity railroad travel and bus lines under pressure, with most of the latter having withered away, whilst the former is still protected under nationalization through the continuing existence of Amtrak . By the 1980s, almost half of the total flying in the world took place in the U.S., and today

13433-399: The shorter great-circle; this is to take advantage of the favourable jet stream , a fast high-altitude tail-wind that assists the aircraft along its ground track saving more time or fuel than the geographically shortest route. Even for flights with the same origin and destination, a flight's duration can be affected by routing, wind, traffic, taxiing time, or aircraft used. For example, on

13566-444: The southern tip of South America . Thus, the term jet stream in these contexts usually implies the northern polar jet stream. The location of the jet stream is extremely important for aviation. Commercial use of the jet stream began on 18 November 1952, when Pan Am flew from Tokyo to Honolulu at an altitude of 7,600 metres (24,900 ft). It cut the trip time by over one-third, from 18 to 11.5 hours. Not only does it cut time off

13699-484: The stratosphere, which, when combined with the Coriolis effect, create the polar night jets, that race eastward at an altitude of about 48 kilometres (30 mi). The polar vortex is circled by the polar night jet. The warmer air can only move along the edge of the polar vortex, but not enter it. Within the vortex, the cold polar air becomes increasingly cold, due to a lack of warmer air from lower latitudes as well as

13832-569: The subtropical jet streams are located close to latitude 30°. These two jets merge at some locations and times, while at other times they are well separated. The northern polar jet stream is said to "follow the sun" as it slowly migrates northward as that hemisphere warms, and southward again as it cools. The width of a jet stream is typically a few hundred kilometres or miles and its vertical thickness often less than five kilometres (16,000 feet). Jet streams are typically continuous over long distances, but discontinuities are also common. The path of

13965-500: The temperature gradient between it and the warmer parts of the globe will continue to diminish with every decade of global warming as the result of this amplification. If this gradient has a strong influence on the jet stream, then it will eventually become weaker and more variable in its course, which would allow more cold air from the polar vortex to leak mid-latitudes and slow the progression of Rossby waves , leading to more persistent and more extreme weather . The hypothesis above

14098-573: The thermal wind relationship, declining speeds are usually found south of the areas with geopotential increases. In 2017, Francis explained her findings to the Scientific American : "A lot more water vapor is being transported northward by big swings in the jet stream. That's important because water vapor is a greenhouse gas just like carbon dioxide and methane. It traps heat in the atmosphere. That vapor also condenses as droplets we know as clouds, which themselves trap more heat. The vapor

14231-399: The tropopause, at the transitions between the polar, Ferrel and Hadley circulation cells , and whose circulation, with the Coriolis force acting on those masses, drives the jet streams. The polar jets, at lower altitude, and often intruding into mid-latitudes, strongly affect weather and aviation. The polar jet stream is most commonly found between latitudes 30° and 60° (closer to 60°), while

14364-428: The vertical direction is primarily between the gravitational force acting on the mass of the parcel and the buoyancy force, or the difference in pressure between the top and bottom surfaces of the parcel. Any imbalance between these forces results in the acceleration of the parcel in the imbalance direction: upward if the buoyant force exceeds the weight, and downward if the weight exceeds the buoyancy force. The balance in

14497-417: The vertical direction is referred to as hydrostatic . Beyond the tropics, the dominant forces act in the horizontal direction, and the primary struggle is between the Coriolis force and the pressure gradient force. Balance between these two forces is referred to as geostrophic . Given both hydrostatic and geostrophic balance, one can derive the thermal wind relation: the vertical gradient of the horizontal wind

14630-568: The way for its eventual merger with Philippine Airlines in March 1941 and made it Asia's oldest airline. It is also the oldest airline in Asia still operating under its current name. Bachrach's majority share in PATCO was bought by beer magnate Andres R. Soriano in 1939 upon the advice of General Douglas MacArthur and later merged with newly formed Philippine Airlines with PAL as the surviving entity. Soriano has controlling interest in both airlines before

14763-431: The winds (note that deflection is leftward in the southern hemisphere). Jupiter 's atmosphere has multiple jet streams, caused by the convection cells that form the familiar banded color structure; on Jupiter, these convection cells are driven by internal heating. The factors that control the number of jet streams in a planetary atmosphere is an active area of research in dynamical meteorology. In models, as one increases

14896-401: The winds are organized into tight jets, rather than distributed more broadly over the hemisphere. One factor that contributes to the creation of a concentrated polar jet is the undercutting of sub-tropical air masses by the more dense polar air masses at the polar front . This causes a sharp north–south pressure (south–north potential vorticity ) gradient in the horizontal plane, an effect which

15029-454: The winter months when the nights are much longer – hence the name referencing polar nights – in their respective hemispheres at around 60° latitude. The polar night jet moves at a greater height (about 24,000 metres (80,000 ft)) than it does during the summer. During these dark months the air high over the poles becomes much colder than the air over the Equator. This difference in temperature gives rise to extreme air pressure differences in

15162-424: The world. Established by aviator Albert Plesman , it was immediately awarded a "Royal" predicate from Queen Wilhelmina . Its first flight was from Croydon Airport , London to Amsterdam , using a leased Aircraft Transport and Travel DH-16 , and carrying two British journalists and a number of newspapers. In 1921, KLM started scheduled services. In Finland , the charter establishing Aero O/Y (now Finnair )

15295-540: The world. The airline soon gained a reputation for reliability, despite problems with bad weather, and began to attract European competition. In November 1919, it won the first British civil airmail contract. Six Royal Air Force Airco DH.9A aircraft were lent to the company, to operate the airmail service between Hawkinge and Cologne . In 1920, they were returned to the Royal Air Force. Other British competitors were quick to follow – Handley Page Transport

15428-590: The year before his death, Post made several attempts at a high-altitude transcontinental flight, and noticed that at times his ground speed greatly exceeded his air speed. German meteorologist Heinrich Seilkopf is credited with coining a special term, Strahlströmung (literally " jet current"), for the phenomenon in 1939. Many sources credit real understanding of the nature of jet streams to regular and repeated flight-path traversals during World War II . Flyers consistently noticed westerly tailwinds in excess of 160 km/h (100 mph) in flights, for example, from

15561-403: Was Aircraft Transport and Travel , formed by George Holt Thomas in 1916; via a series of takeovers and mergers, this company is an ancestor of modern-day British Airways . Using a fleet of former military Airco DH.4 A biplanes that had been modified to carry two passengers in the fuselage , it operated relief flights between Folkestone and Ghent , Belgium. On July 15, 1919, the company flew

15694-585: Was Deutsche Luft-Reederei established in 1917 which started operating in February 1919. In its first year, the D.L.R. operated regularly scheduled flights on routes with a combined length of nearly 1000 miles. By 1921 the D.L.R. network was more than 3000 km (1865 miles) long, and included destinations in the Netherlands, Scandinavia and the Baltic Republics. Another important German airline

15827-455: Was Junkers Luftverkehr , which began operations in 1921. It was a division of the aircraft manufacturer Junkers , which became a separate company in 1924. It operated joint-venture airlines in Austria, Denmark, Estonia, Finland, Hungary, Latvia, Norway, Poland, Sweden and Switzerland. The Dutch airline KLM made its first flight in 1920, and is the oldest continuously operating airline in

15960-525: Was a former mayor of St. Petersburg, who paid $ 400 for the privilege of sitting on a wooden bench in the open cockpit. The Airboat line operated for about four months, carrying more than 1,200 passengers who paid $ 5 each. Chalk's International Airlines began service between Miami and Bimini in the Bahamas in February 1919. Based in Ft. Lauderdale , Chalk's claimed to be the oldest continuously operating airline in

16093-645: Was a mistake." Congress passed the Air Transportation Safety and System Stabilization Act (P.L. 107–42) in response to a severe liquidity crisis facing the already-troubled airline industry in the aftermath of the September 11 attacks . Through the ATSB Congress sought to provide cash infusions to carriers for both the cost of the four-day federal shutdown of the airlines and the incremental losses incurred through December 31, 2001, as

16226-508: Was able to reconstruct jet stream patterns over the past 1,250 years based on Greenland ice cores , and found that all of the recently observed changes remain within range of natural variability: the earliest likely time of divergence is in 2060, under the Representative Concentration Pathway 8.5 which implies continually accelerating greenhouse gas emissions. The polar-night jet stream forms mainly during

16359-668: Was also one of the world's first major airlines which began its operations without any support from the Government. Jet stream Jet streams are fast flowing, narrow, meandering air currents in the atmospheres of the Earth , Venus, Jupiter, Saturn, Uranus, and Neptune. On Earth, the main jet streams are located near the altitude of the tropopause and are westerly winds (flowing west to east). Jet streams may start, stop, split into two or more parts, combine into one stream, or flow in various directions including opposite to

16492-418: Was established in 1919 and used the company's converted wartime Type O/400 bombers with a capacity for 12 passengers, to run a London - Paris passenger service. The first French airline was Société des lignes Latécoère , later known as Aéropostale, which started its first service in late 1918 to Spain. The Société Générale des Transports Aériens was created in late 1919, by the Farman brothers and

16625-450: Was granted by the federal government body after reviewing the necessity at the national assembly. The Hanjin occupies the largest ownership of Korean Air as well as few low-budget airlines as of now. Korean Air is one of the four founders of SkyTeam , which was established in 2000. Asiana Airlines joined Star Alliance in 2003. Korean Air and Asiana Airlines comprise one of the largest combined airline miles and number of passenger served at

16758-481: Was inaugurated in 1932 with the Handley Page HP 42 airliners. Further services were opened up to Calcutta , Rangoon , Singapore , Brisbane and Hong Kong passengers departed London on 14 March 1936 following the establishment of a branch from Penang to Hong Kong. France began an air mail service to Morocco in 1919 that was bought out in 1927, renamed Aéropostale , and injected with capital to become

16891-631: Was much weaker and more negative during the Last Glacial Maximum , and suggesting that warmer periods have stronger positive phase AO, and thus less frequent leaks of the polar vortex air. However, a 2012 review in the Journal of the Atmospheric Sciences noted that "there [has been] a significant change in the vortex mean state over the twenty-first century, resulting in a weaker, more disturbed vortex.", which contradicted

17024-614: Was signed in the city of Helsinki on 12 September 1923. Junkers F.13 D-335 became the first aircraft of the company, when Aero took delivery of it on 14 March 1924. The first flight was between Helsinki and Tallinn , capital of Estonia , and it took place on 20 March 1924, one week later. In the Soviet Union , the Chief Administration of the Civil Air Fleet was established in 1921. One of its first acts

17157-468: Was stressed by reviews in 2013 and in 2017. A study in 2014 concluded that Arctic amplification significantly decreased cold-season temperature variability over the Northern Hemisphere in recent decades. Cold Arctic air intrudes into the warmer lower latitudes more rapidly today during autumn and winter, a trend projected to continue in the future except during summer, thus calling into question whether winters will bring more cold extremes. A 2019 analysis of

17290-620: Was the Handley Page W8f City of Washington , delivered on 3 November 1924. In the first year of operation the company carried 11,395 passengers and 212,380 letters. In April 1925, the film The Lost World became the first film to be screened for passengers on a scheduled airliner flight when it was shown on the London-Paris route. Two French airlines also merged to form Air Union on 1 January 1923. This later merged with four other French airlines to become Air France ,

17423-592: Was the world's first airline . It was founded on November 16, 1909, with government assistance, and operated airships manufactured by The Zeppelin Corporation . Its headquarters were in Frankfurt . The first fixed-wing scheduled airline was started on January 1, 1914. The flight was piloted by Tony Jannus and flew from St. Petersburg, Florida , to Tampa, Florida , operated by the St. Petersburg–Tampa Airboat Line . The earliest fixed wing airline in Europe

17556-577: Was the German airship company DELAG , founded on November 16, 1909. The four oldest non-airship airlines that still exist are the Netherlands' KLM (1919), Colombia's Avianca (1919), Australia's Qantas (1920) and the Russian Aeroflot (1923). Airline ownership has seen a shift from mostly personal ownership until the 1930s to government-ownership of major airlines from the 1940s to 1980s and back to large-scale privatization following

17689-404: Was to help found Deutsch-Russische Luftverkehrs A.G. (Deruluft), a German-Russian joint venture to provide air transport from Russia to the West. Domestic air service began around the same time, when Dobrolyot started operations on 15 July 1923 between Moscow and Nizhni Novgorod. Since 1932 all operations had been carried under the name Aeroflot . Early European airlines tended to favor comfort –

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