From March to 29 June 1944, the 405th operated out of the RAF Christchurch. After setting up camp and training over England, the group began combat operations over France. During this period their primary task was ground attack ahead of the coming Operation Overlord invasion of Normandy. The group disrupted German positions and transportation infrastructure. Train locomotives were a favorite target. The group destroyed the Seine River bridge at Mantes-Gassicourt, northeast of Paris, just before the invasion, to inhibit movement of German materiel. The group was grounded during the 6 June invasion activities because Allied command was concerned that inexperienced anti-aircraft batteries would mistake P-47s for the German Focke-Wulf Fw 190. The 405th resumed flying on 10 June, providing close air support to the beachhead. On 18 June 1944, the group was redesignated to the 405th Fighter Group. A few weeks after the invasion, the 405th packed up and moved to a POE near Southampton.