An airline provides air transport services for passengers or freight, generally with a recognized operating certificate or license. Airlines lease or own their aircraft with which to supply these services and may form partnerships or alliances with other airlines for mutual benefit.

Airlines vary from those with a single airplane carrying mail or cargo, through full-service international airlines operating many hundreds of airplanes. Airline services can be categorized as being intercontinental, intracontinental, or domestic and may be operated as scheduled services or charters.

The First Airlines

DELAG, Deutsche Luftschiffahrts-Aktiengesellschaft (German: acronym for "German Airship Transport Corporation") was the world's first airline. It was founded on November 16, 1909 with government assistance, and operated airships manufactured by Zeppelin Corporation. Its headquarters were in Frankfurt. (Note: Americans, such as Rufus Porter and Frederick Marriott, attempted to start airlines in the mid-19th century, focusing on the New York-California route. Those attempts foundered due to such mishaps as the aircraft catching fire and the aircraft being ripped apart by spectators.) The five oldest non-dirigible airlines that still exist are Australia's Qantas, Netherland's KLM, Colombia's Avianca, Czech Republic's Czech Airlines and Mexico's Mexicana. KLM first flew in May 1920 while Qantas (for the Queensland and Northern Territory Aerial Services Limited) was founded in Queensland, Australia in late 1920. 1.

Early Development

Tony Jannus conducted the United States' first scheduled commercial airline flight on 1 January 1914 for the Saint Petersburg-routes, Braniff Airways, American Airlines, Delta Air Lines, United Airlines (originally a division of Boeing), Trans World Airlines, Northwest Airlines, and Eastern Air Lines, to name a few.

Passenger service during the early 1920s was sporadic: most airlines at the time were focused on carrying bags of mail. In 1925, however, 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 a crusade to create an air network that would link America to the world, and he achieved this goal through his airline, Pan American World Airways, 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.