How many B-17s took off from Midway for the first air attack ?
The B-17s rendezvous with 55 P-51s from Pyriatyn , bomb the oil refinery and marshaling yard at Drohobycz , Poland ( one returns to the USSR because of mechanical trouble ) , and then proceed to Italy ; Fifteenth Air Force P-51s meet the formation one hour after the attack and escort the B-17s to Foggia .