It was July 31, 1944, and Army Air Corps pilot Lt. Henry Supchak was flying his 33rd bombing mission over Munich, Germany, when his B-17 bomber, nicknamed “Priority Gal,” was riddled by anti-aircraft fire. Sputtering and billowing black smoke, Supchak knew the aircraft would never make it back to base in Bassingbourn, England, 650 miles away. With two dead engines, the aircraft was plummeting fast — over Nazi-occupied Austria. “I said, ‘Fellas get your chutes on!’ ” and ordered them to jump. Alone now, with a two-inch piece of shrapnel dug into his right leg, Supchak desperately needed to get...