Ward Thomas joined RAF Bomber Command in 1941 and trained as a navigator and pilot in South Africa. He joined 100 Squadron as a Lancaster pilot and was later moved to 550 Squadron stationed in Grimsby. He flew 36 trips over France and Germany over the course of the war, including taking part in the Nuremberg raid of March 1944 during which Bomber Command suffered its heaviest loses. He was awarded the Croix de Guerre for his involvement in bombing raids on the German Panzer training camp at Mailly-le-Camp in advance of the Normandy landings in June 1944. He also received the DFC "for utmost fortitude, courage and devotion to duty in air operations" during the War. By the time he left the RAF Ward Thomas had achieved the rank of flight lieutenant.