Secretary of Defense Chuck Hagel, right foreground, bows his head for the invocation during a change of command and retirement ceremony for U.S. Air Force Gen. William M. Fraser III May 5, 2014, at Scott Air Force Base, Ill. Fraser served as the commander of U.S. Transportation Command before retiring from the Air Force after 40 years of service. (DoD photo by Mass Communication Specialist 1st Class Daniel Hinton, U.S. Navy/Released)