U.S. Air Force Gen. William M. Fraser III, center, salutes Secretary of Defense Chuck Hagel after relinquishing command of U.S. Transportation Command May 5, 2014, at Scott Air Force Base, Ill. Gen. Paul J. Selva, right, assumed command from Fraser, who retired from the Air Force after 40 years of service. (DoD photo by Mass Communication Specialist 1st Class Daniel Hinton, U.S. Navy/Released)