The high cost of the Allied air offensive during World War II. On August 29, 1944, the 15th U.S. Army Air Force unleashed 500 bombers against oil and rail targets throughout central Europe. It dispatched the 20th Squadron of the 2nd Bombardment Group on what they regarded as an easy assignment: attack the Privoser Oil Refinery and associated railroad yards at Moravska Ostrava, Czechoslovakia. This "milk run" deteriorated into the bloodiest...