U.S. Air Force Academy graduates throw their hats in the air. U.S. Air Force Academy graduates throw their hats in the air in celebration as the Thunderbirds fly overhead signaling the end of the Air Force Academy graduation ceremony at Colorado Springs, Colo., on May 30, 2007. Secretary of Defense Robert M. Gates delivered the commencement address to the 976-member graduating class. SHARE: Download: Full Size (0.05 MB) Credit: VIRIN: 067557-Z-BXF29-598.jpg Photo Gallery