Airlines as commercial enterprises began in Europe, though not in the form that is generally recognized nowadays. Davies (2017) names the German DELAG, which operated zeppelins between 1909 and 1935, as the first airline. Following its emergence, other nations also started creating airlines, such as Aircraft Transport and Travel in the UK and Svensk Lufttrafik in Sweden. However, most of these organizations eventually failed or merged with other firms until the emergence of KLM, the first airline to still operate today, in 1919 (Berend, 2016). The proliferation of airlines continued afterward, eventually making Europe a prominent aviation market.
The USA began creating airlines shortly after the creation of DELAG, focusing on winged aircraft from the beginning. Grove (2016) discusses the St. Petersburg-Tampa Airboat Line, the first airline to operate an airplane, flying for 18 miles and carrying 1,204 passengers before shutting down due to insolvency. Similar to Europe, other carriers began emerging afterward, with the first one to survive nowadays, Delta, founded in 1925. In general, the 1920s marked a period of rapid expansion of air travel in the US, which also made it a major market in the 20th century.
Asian nations lagged behind Western ones in their aviation development, only starting rapid growth in the second half of the 20th century. Japan Air Transport Institute, a private enterprise, was among the first, emerging in 1922, though Japan Air Transport Company would absorb it in 1928 (Davies, 2016). Other nations would follow, with Korean National Airlines formed in 1946 and Malayan Airways starting operations in 1947. All of these airlines would then undergo substantial changes, with deregulation taking place later than in Western nations and the growth period delayed.
References
Berend, I. T. (2016). An economic history of twentieth-century Europe: Economic regimes from laissez-faire to globalization. Cambridge University Press.
Davies, N. (2017). Beneath another sky: A global journey into history. Penguin Books Limited.
Davies, R. E. G. (2016). Airlines of the jet age: A history. Smithsonian.
Grove, T. (2016). Milestones of flight: From hot-air balloons to SpaceShipOne. ABRAMS.