In 1936 it became "No 501 (County of Gloucester) Squadron", changing the name to embrace a larger area of recruitment.

[3] On 1 May 1936 it was transferred to the Auxiliary Air Force and in July of that year the squadron converted to Hawker Harts.

"Ginger" Lacey of 501 Squadron shot down three enemy aircraft in a single day to win the Croix de Guerre.

It subsequently served at RAF Kenley, south London, commanded by S/L Harry Hogan, until 17 December 1940 by which time the squadron had claimed 149 enemy aircraft destroyed.

In April 1943 the squadron returned to Tangmere for bomber escort work – some pilots being issued with the Spitfire Mk IXc.

Between November 1943 and October 1944 the squadron formed part of Air Defence of Great Britain (ADGB).

[14] During August 1944, the squadron began converting to the Tempest Mk.V at RAF Manston, for the purposes of Operation Diver – the interception of V-1 missiles.

[19][20] Among others who achieved fighter ace status were Ken Mackenzie,[21] "Ginger" Lacey,[22] Stanisław Skalski,[23] Robert Dafforn,[24] Paul Farnes DFM, Kenneth Lee,[25] Donald McKay, and Percy Morfill.

In February 1957, Flt Lt John Crossley flew Vampire FB.9 jet WR260 beneath the Clifton Suspension Bridge, before a fatal crash into Leigh Woods.