- Aldergrove was selected to be the Royal Flying Corps training establishment during the First World War.
- After the war Aldergrove remained open for Royal Air Force aircraft and for the fledgling civil traffic to and from Northern Ireland.
- In 1921 King George V and Queen Mary visited Northern Ireland. Aircraft landed at Aldergrove with cameramen and reporters and returned to London with newsreel films and photographs of the event.
- 1925 saw Northern Ireland's own Special Reserve unit No 502 (Ulster) Squadron RAF formed at Aldergrove.
- By 1934 Aldergrove was Northern Ireland's civil airport
- 1934 saw the first London service begin to Nutts Corner. The flight flew from Croyden, via Birmingham and Manchester to Belfast and was operated by Railway Air Services.
- During the second World War, Aldergrove remained an airbase.
- After the war civil flights were moved back to Aldergrove due to less variable weather conditions than at Nutts Corner.
- In 1963 operations were transferred to Aldergrove and the first passenger flight to land was a BEA Viscount from Manchester.
- In October 1963 HRH Queen Elizabeth the Queen Mother reopened Aldergrove as a civil airport and introduced the terminal building
- The first regular jet service began in 1966 with a British United BAC 1-11 to Gatwick
- By 1969 annual passengers at the airport had reached 1 million
- 30 years on Belfast airport is the principal gateway to the north of Ireland and sees over 4 million passengers through the terminal each year.