Complex sentence: He flew 607 hours on 181 combat missions in P-39 and then P-38 aircraft, and scored 22 aerial victories against Japanese fighter aircraft, the fourth highest number of enemy aircraft destroyed by an Army Air Corps pilot in the Pacific Theater of Operations.
Split into simpler sentences: He flew 607 hours on 181 combat missions in P-39 and then P-38 aircraft. He scored 22 aerial victories against Japanese fighter aircraft, the fourth highest number of enemy aircraft destroyed by an Army Air Corps pilot in the Pacific Theater of Operations.