No. 504 Squadron were equipped with the Hurricane Mk1 until July 1941 when they upgraded to the Hurricane MkIIb until November 1941. From October 1941 the Squadron was equipped with the Spitfire MkIIa and MkIIb until February 1942. From then until the end of the war the Squadron had many variants of Spitfire with the MkVb, MkVc, MkVI, MkIXb, MkVb and the MkIXe. 

504 Squadron served at  RAF Exeter, Clyst Honiton from the 18 December 1940 until the 21 July 1941 equipped with the Hawker Hurricane. S/Ldr. J. Sample, DFC, was the Commanding Officer of the Squadron until March 1941 and then S/Ldr. M. Rook, DFC, took over until the departure from RAF Exeter in July.

Because of the amount of raids to the airfield the men were moved to a house in Pinhoe, but when on duty they slept on bunks inside surface shelters which formed part of the 'W' shaped aircrat pens around the airfield perimeter. Pilots from the squadron were billeted in the Gypsy Hill Hotel also in Pinhoe.

During the early part of 1941 the squadron operated between RAF Exeter and RAF Weston Zoyland. 

The Squadron crest was awarded in October 1941 and featured an Oak Tree. The ‘Major Oak’ appears in the Arms of Nottingham.

The Squadron Motto was - latin: Vindicat in ventis – It avenges in the winds.

​The Squadron aircraft code was TM.