The Royal Auxiliary Air Force (RAuxAF), formerly the Auxiliary Air Force (AAF), together with the Air Force Reserve, is a component of His Majesty's Reserve Air Forces. It provides a primary reinforcement capability for the regular service, and consists of paid volunteers who give up some of their weekends, evenings and holidays to train at one of a number of squadrons around the United Kingdom. Its current mission is to provide trained personnel in support of the regular RAF.

The Royal Air Force Volunteer Reserve (RAFVR) was established in 1936 to support the preparedness of the U.K. Royal Air Force in the event of another war. The Air Ministry intended it to form a supplement to the Royal Auxiliary Air Force (RAuxAF), the active reserve for the RAF, by providing an additional non-active reserve. However during the Second World War the high demand for aircrew absorbed all available RAuxAF personnel and led the RAFVR to quickly become the main pathway of aircrew entry into the RAF. It was initially composed of civilians recruited from neighbourhood reserve flying schools, run by civilian contractors with largely RAF-trained flying instructors as well as other instructors in related air war functions, such as observers and wireless operators.