Upon arrival in the European Theater of Operations the group became part of IX Fighter Command. The group's station in England was RAF Winkton, an unimproved field, where it received 75 Republic P-47 Thunderbolts by 16 April. By 1 May, it was ready to fly its first combat mission, a fighter sweep over Normandy. Later in the month, it began to fly Noball missions, strikes on V-1 flying bomb launching sites. For the rest of the month, the 404th helped prepare for Operation Overlord, the Normandy invasion by bombing and strafing targets in northern France. The group's squadrons provided top cover for landings in Normandy on 6 and 7 June 1944.