A U.S. Air Force KC-10 Stratotanker moves into position to refuel a C-17 Globemaster III during the mobility air forces exercise as part of the U.S. Air Force Weapons School on Nellis Air Force Base, Nev., May 23, 2012. The Air Force Weapons School is a five-and-a-half-month training course which provides selected officers with the most advanced training in weapons and tactics employment. MAFEX is the culmination exercise for mobility assets participating in the weapons school.