On 12 July 1940, Fiske joined No. 601 Squadron RAF, a Hawker Hurricane unit, at RAF Tangmere, West Sussex, the so-called "Millionaires' Squadron", carrying out his first sorties with the squadron on 20 July, when he flew two patrols. On 16 August 1940, in the midst of the Battle of Britain, No. 601 Squadron RAF were scrambled to intercept a squadron of German dive-bombers. Fiske was flying Hurricane serial number "P3358". The Squadron destroyed eight Junkers Ju 87 Stukas, but after just 15 minutes of flying time, a German gunner put a bullet through Fiske's fuel tank.