KLM – October 1919
KLM (Koninklijke Luchtvaart Maatschappij in full) is generally recognized as the oldest airline still in service, under its original name. It was established in October 1919. //

Avianca – December 1919
Avianca comes in very close behind KLM, founded just a few months later, in December 2019. It started life in Barranquilla, backed by German expatriates, as SCADTA (The Colombia-German Air Transport Company). //

Qantas – November 1920
Australian airline Qantas makes it to third place. Queensland and Northern Territory Aerial Services (Qantas) started in 1920 with a mission to service the sparsely populated northern regions of the country. //

Overseas services began in 1934 when Qantas and Imperial Airways (a predecessor of British Airways) jointly formed Qantas Empire Airways Limited (QEA). The route to the UK with Shorts S23 Empire flying boats in 1938 took nine days. //

Qantas was nationalized after the Second World War, and services continued with both flying boats and aircraft such as the Avro Lancastrian and the DC4. Jet service began with the 707 in 1959. For several years in the 1980s, it operated an all 747 fleet, making its retirement particularly sad.