Staff Sgt. David Morales, a 51st Operations Support Squadron airfield management operations supervisor, watches a jet land on flightline Nov. 3, 2015, at Osan Air Base, South Korea. Morales and more than 16,000 other personnel are participating in readiness exercise Vigilant Ace 16, a large-scale exercise designed to test the combat capabilities and enhance the interoperability of the U.S. and South Korean air forces. (U.S. Air Force photo/Staff Sgt. Benjamin Sutton)