The date of the first airline service may differ from the foundation date.
| Airline | Established | Ceased operations | Notes |
 DELAG | 01909-11-16 November 16, 1909 | 01935 1935 | Operated Zeppelins, aircraft taken over by state-sponsored airline. |
 Aircraft Transport and Travel | 01916-10-05 October 5, 1916 | 01921 1921 | The first international scheduled service in 1919. |
 Chalk's Ocean Airways | 01917 1917 | 02007 2007 | Became Chalk's International Airlines. |
 Det Danske Luftfartselskab | 01918-10-29 October 29, 1918 | 01946 1946 | Services started August 7, 1920. Part of SAS since 1946. |
 Société des lignes Latécoère | 01918-12-25 December 25, 1918 | 01932 1932 | Rebranded as Aéropostale in 1927. In 1933 its assets were incorporated into Air France. |
 Svenska Lufttrafik | 01919-02-07 February 7, 1919 | 01921 1921 | |
| Lignes Aériennes Farman | 01919-02-08 February 8, 1919 | 01933-10-07 October 7, 1933 | Merged with 4 other airlines to form Air France. |
| Grands Express Aériens | 01919-03-20 March 20, 1919 | 01923-01-01 January 1, 1923 | Merged with Compagnie des Messageries Aériennes to form Air Union. |
| Compagnie des Messageries Aériennes | 01919-04-18 April 18, 1919 | 01923-01-01 January 1, 1923 | Merged with Grands Express Aériens to form Air Union. |
| Daimler Airway | 01919-06-07 June 7, 1919 | 01924 1924 | Merged with 3 other airlines to form Imperial Airways. |
 KLM | 01919-10-07 October 7, 1919 | Still in operation | Operations stopped during World War II apart from the operations in the Dutch Antilles in the Caribbean. Merged with Air France in 2004. |
 SCADTA | 01919-12-05 December 5, 1919 | 01940-06-14 June 14, 1940 | Merged with SACO to form Avianca on June 14, 1940. |
| Handley Page Transport | 01919 1919 | 01924-03-31 March 31, 1924 | Merged with 3 other airlines to form Imperial Airways. |
| Instone Air Line | 01919 1919 | 01924 1924 | Merged with 3 other airlines to form Imperial Airways. |
/ Compagnie Franco-Roumaine de Navigation Aérienne | 01920-04-23 April 23, 1920 | 01933 1933 | Merged with 4 other airlines to form Air France. |
 Qantas | 01920-11-16 November 16, 1920 | Still in operation | World's oldest continuously operating airline. |
 Mexicana | 01921-07-12 July 12, 1921 | Still in operation | |
| West Australian Airways | 01921-12-05 December 5, 1921 | 01936-06-12 June 12, 1936 | Became part of Australian National Airways. |
| Aeromarine West Indies Airways | 01921 1921 | 01924 1924 | |
 Malert | 01922-11-19 November 19, 1922 | 01944 1944 | |
| Air Union | 01923-01-01 January 1, 1923 | 01933-10-07 October 7, 1933 | Merged with 4 other airlines to form Air France. |
 Aeroflot | 01923-02-09 February 9, 1923 | Still in operation | |
 SABENA | 01923-05-23 May 23, 1923 | 02002-02 February 2002 | Succeeded by SN Brussels Airlines. |
| British Marine Air Navigation Co Ltd | 01923-08 August 1923 | 01924 1924 | Merged with 3 other airlines to form Imperial Airways. |
 Czech Airlines | 01923-10-06 October 6, 1923 | Still in operation | |
 Finnair | 01923-11-01 November 1, 1923 | Still in operation | Founded as Aero O/Y, name changed to Finnair in 1968. |
| Zakavia | 01923 1923 | 01925 1925 | |
| Imperial Airways | 01924 1924 | 01939 1939 | Amalgamated to form British Overseas Airways Corporation - itself merged to found British Airways. |
| AB Aerotransport | 01923-06-02 June 2, 1923 | 01950 1950 | Formed SAS. |
| Tajik Air | 01923-09-03 September 3, 1923 | Still in operation | |
 Delta Air Lines | 01924-05-30 May 30, 1924 | Still in operation | Founded as Huff Daland Dusters. |
| CIDNA | 01925-01-01 January 1, 1925 | 01933-10-07 October 7, 1933 | The former company - CFRNA (French-Romanian Company For Air Navigation) was the first international transcontinental company. Incorporated into Air France. |
 Lloyd Aéreo Boliviano | 01925-09-15 September 15, 1925 | 02007-04-01 April 1, 2007 | Airline is going to be replaced with Boliviana de Aviación. |
| Western Air Express | 01925 1925 | 01986-09-09 September 9, 1986 | |
 Deutsche Luft Hansa Aktiengesellschaft | 01926-01-06 January 6, 1926 | 01945 1945 | Operations suspended following Germany's defeat. Rebranded on August 6, 1954, as Lufthansa. Resumed scheduled service on April 1, 1955. |
 Western Canadian Airways | 01926-03 March 1926 | 01930 1930 | Amalgamated with several Eastern Canadian carriers forming Canadian Airways. |
| Varney Airlines | 01926-04-06 April 6, 1926 | 01934 1934 | Merged with National Air Transport to form United Airlines following the Air Mail scandal in 1933 and the Air Mail Act of 1934. |
| Northwest Airlines | 01926 1926 | Still in operation | Merging with Delta Airlines. |
| Colonial Air Transport | 01926 1926 | 01930 1930 | Formed American Airlines. |
 Serviços Aéreos Cruzeiro do Sul | 01926 1926 | 01993 1993 | Formed Varig. |
