Tech. Sgt. Christian MacKenzie was a special operations flight engineer on a MH-53 Pave Low helicopter until he was shot down in Iraq April 13, 2004. Despite losing the vision in his left eye, Sergeant MacKenzie continues to serve on active duty in the Air Force as a flight attendant based at Andrews Air Force Base, Md. (U.S. Air Force photo/Staff Sgt. D. Myles Cullen)