Brig. Gen. Mark A. Kyle, commander, 4th Air Force, addresses the crowd immediately after assuming command during change of command ceremony at March Air Reserve Base, Calif., March 12, 2011. General Kyle is the new commander of 4th Air Force, taking the place of former commander, Maj. Gen. Eric W. Crabtree. (U.S. Air Force photo/Master Sgt. Linda Welz)