A U.S. Air Force F-16 Fighting Falcon pilot waves to the boom operator of a KC-135 Stratotanker during an air-to-air refueling mission over Spangdahlem Air Base, Germany, May 30, 2017. During the refueling training approximately 60,000 pounds of jet fuel were used to fuel 10 F-16 Fighting Falcons. (U.S. Air Force photo by Senior Airman Dawn M. Weber)