The Air Corps provides the air defence function of the Irish Defence Forces (Óglaigh na hÉireann), in support of the Army and Naval Service, together with such other roles as may be assigned by the Government (e.g. Search and Rescue, Ministerial Air Transport Service).
The origin of the Air Corps goes back to the Anglo-Irish Treaty talks of 1921, when a Martinsyde Type A Mark II biplane was purchased in order to allow Michael Collins to escape back to Ireland if the talks failed. In the event it was not needed for this mission, and it became the first Irish military aircraft, arriving in June 1922.
By the end of 1922 the Air Corps comprised ten aircraft (including 6 Bristol F2B fighters from the First World War), and about 400 men.
During the 1930s funds were not plentiful, but in 1938 four Gloster Gladiator biplane fighters were delivered -- a further eight were ordered but were embargoed by the outbreak of the Second World War, referred to in neutral Ireland as "The Emergency".
During The Emergency there is no record of Air Corps planes engaging any belligerent aircraft, although dozens of escaped barrage balloons were shot down. 163 belligerent aircraft force-landed in Ireland during the war, and in this way the Air Corps acquired a Lockheed Hudson, a Fairey Battle, and three Hawker Hurricanes.
The Hurricane gave the Air Corps a proven modern fighter, and at some stage no fewer than 20 flew in Irish colours.
After the war, the Hurricanes were replaced by Supermarine Seafires and a few two-seat Spitfire trainers. The de Havilland Dove became the Corps' transport aircraft. The jet age arrived on 30 June 1956 when the Corps took delivery of a de Havilland Vampire T.55 trainer.
In 1963 the Corps took delivery of its first helicopters, Allouette IIIs , of which seven remain in service at the start of the 21st century. In their time, 3,300 people have been assisted by these helicopters in their Search and Rescue and air ambulance roles.
In the mid-1970s the expansion of the Ministerial Air Transport Service (MATS) following Ireland's accession to the European Economic Community (now the European Union) led to the acquisition of the Corps' first business jet, a BAe 125-700.
As part of its obligations to the European Union, Ireland is responsible for patrolling 132,000 square miles (342,000 km²) of sea. In order to do this, the Air Corps employed three Beech King Air turboprops, later replaced by two CASA CN235 maritime patrol aircraft.
In its MATS role, following Ireland's assumption of the EU Presidency the Corps leased a Grumman Gulfstream III which in 1990 became the first Irish military aircraft to circumnavigate the world, conveying the Foreign Affairs Minister to Ottawa, Anchorage, Sapporo, Brunei, Kuching, Bombay, Dubai and Rome before returning home. In more recent times, a Grumman Gulfstream IV has been leased.