This from the wikipedia story on Folkestone Racecourse:-
RAF Westenhanger.The racecourse was first used by aviation when a flying meeting was held in September 1910, three aircraft were present watched by a large crowd. Between 1940 and 1941 the racecourse was used as a decoy airfield with dummy aircraft placed to look like an active airfield. On 23 April 1944 660 Squadron, an army cooperation squadron of the Royal Air Force, arrived at what was then known as RAF Westenhanger after the nearby village. The squadron based in a tented camp was equipped with Auster Mark IV single-engined liaison aircraft and used the racecourse to practice operations with local army units. On 12 July 1944 the squadron of 12 Austers escorted by a Supermarine Walrus rescue flying boat left Westenhangar for France. The airfield was then restored back to use as a racecourse. Rubble from wartime buildings can be seen on the north side of the straight course where it meets the oval.