U.S. Air Force Staff Sgt. Mathew Leightner, right, and Staff Sgt. Nathaniel Inwood, both assigned to the 517th Aircraft Maintenance Unit, prepare a C-17 Globemaster III aircraft for a mission during Cope Tiger 13 at Udon Thani Royal Thai Air Force Base, Thailand, March 15, 2013. Cope Tiger is an annual multilateral aerial exercise designed to improve readiness and cooperation between U.S., Thai and Singaporean forces. (U.S. Air Force photo by 2nd Lt. Jake Bailey/Released)