No. 605 Squadron was formed as an Auxiliary Air Force Squadron. Initially formed as a bomber unit, it became a fighter squadron prior to the Second World War and was one of the most successful participants of the Battle of Britain. It also had the distinction of being active during the war at two fronts at a time, when the squadron was split up between Malta and the Dutch East Indies. In its last incarnation as an active flying unit, the squadron served as the first jet fighter unit in the post-war Royal Auxiliary Air Force; 616 having already flown Gloster Meteors during the war. No. 605 Squadron was reformed as a RAuxAF Logistic Support Squadron (LSS) on 1 Nov 2014 within No. 85 Expeditionary Logistics Wing of the RAF A4 Force. On the 1 January 2019, the Reserve Logistic Support Wing (RLSW) was established with 501, 504 and 605 LSS Squadron's moving from No. 85 Wing RAF to form RLSW.

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.