Activated on 1 October 1942 at RAF Duxford, England by special authority of the USAAF by Eighth Air Force. Assigned to VIII Fighter Command, equipped with a mixture of United States personnel reassigned from the 31st and 52d Fighter Groups, and Americans transferred from the Royal Air Force who had volunteered to join the RAF prior to the United States entry into the European War, 11 December 1941. Demobilized and inactivated, 7 November 1945. Unit designation allocated to Pennsylvania Air National Guard, re-designated as 146th Fighter Squadron, 24 May 1946.