 Blakeslee successfully had the group re-equipped with Mustangs, and it is almost certain that on 6 March 1944, he was the first American plane over Berlin in his Mustang.The Fourth destroyed more enemy planes in the air and on the ground than any other fighter group of Eighth Air Force.The group operated first with Spitfires but changed to P-47s in March 1943 and to P-51s in late February early March 1944.