Thunder aircraft begin to arrive at Kentucky Air Guard Base
Two U.S. Air Force F-22 Raptor fighter jets taxi into the Kentucky Air National Guard Base in Louisville, Ky., on April 18, 2012, prior to this weekend's 22nd annual Thunder Over Louisville air show. The Raptor Demo Team, based at Langley Air Force Base, Va., will be one of the show's marquee events. The Kentucky Air Guard is once again supporting military aircraft for Thunder, which has grown to become one of the largest air shows in North America, organizers say. (U.S. Air Force Photo by Maj. Dale Greer)