How many B-17s took off from Midway for the first air attack ?
2 July 1944 : The Eighth Air Force P-51 Group joined with other Fifteenth Air Force fighters in escorting 509 heavy bombers on a mission to three objectives in the Budapest , Hungary area ; a marshaling yard ( 253 aircraft ) ; Vecses Airfield ( 142 aircraft ) and the Shell Oil Refinery ( 114 aircraft ) .