U.S. Air Force Staff Sgt. Alicia Aguilera, U.S. Air Force Air Demonstration Squadron "Thunderbirds" commander's support staff specialist, chains down a maintenance trailer on a C-17 Globemaster, in preparation to depart Graf Ignatievo Air Base, Bulgaria for RAF Waddington, U.K. June 28, 2011. The Thunderbirds will perform in nine countries during their six-week European tour, fostering international goodwill and representing America's Airmen around the globe.