St. Athan, in the Vale of Glamorgan, has played a vital role in aircraft maintenance and training since the airfield’s official opening on 1 September 1938. The first unit to form at St. Athan was No 4 School of Technical Training (SoTT) and it has been continuously present at the airfield ever since. However, a defence announcement in September 2015 indicated that the School will soon be moving to Cosford. The unit was initially formed to train airframe and engine fitters and mechanics but also trained Flight Engineers from 1942 due to the increased wartime demand for aircrew. A huge number of both military and civilian staff have been based at the airfield, in 1944 there was accommodation for 14,000 personnel, a very large number for a wartime station.

No 19 Maintenance Unit (MU) was formed in 1939, as a civilian manned unit focusing on this role. During the latter part of the war especially, St. Athan was used for the storage of a large number of aircraft. These could also be moved more than four miles along dispersal tracks to Llandow. St. Athan continued to be used for aircraft storage for decades of the airfield’s life. No 32 MU was also established in 1939 and later amalgamated with No 19 MU to form an Engineering complex at the site.

Other units based at St. Athan during the war included No 11 Group Pool, operating Hawker Hurricane fighters. This unit aimed to provide trained pilots to operational squadrons where required immediately. The Pool moved to Sutton Bridge in March 1940. The airfield’s location meant that a number of training units were moved to St. Athan in an attempt to protect them from air attack, though Luftwaffe raids did cause some serious damage and fatalities during 1941. Avro Ansons and Airspeed Oxfords were among the aircraft operated by units such as the School of Air Navigation, Nos 12 and 14 Radio Schools later using Ansons in strength between 1943 and 1946.

After the end of the Second World War, St. Athan remained an important engineering training centre for the RAF, a role that it continues as of today (2015). The airfield was the site of the Head Office of the Defence Aviation Repair Agency (DARA) and later the Defence Support Group which was responsible for the maintenance and repair of RAF, Royal Navy and Army aircraft. However, the last RAF aircraft to be maintained at St. Athan, a Vickers VC10, left in February 2012 and doubts remain over the long-term future of the airfield. Welsh Government plans aim to transfer the airfield to civilian hands by 2019.

The hangars at St. Athan, of which there are over fifty, are divided into two main groups, East Camp and West Camp. There have been various changes to the buildings since the Second World War but many remain as they were. The general layout remains the same, although the airfield now operates a single runway instead of the original three.