Secretary of Defense Chuck Hagel shakes hands with U.S. Air Force Gen. Paul J. Selva, the incoming commander of U.S. Transportation Command, during a change of command ceremony May 5, 2014, at Scott Air Force Base, Ill. Selva assumed command from Gen. William M. Fraser III, seated, center right, 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)