U.S. Air Force Chief of Staff Gen. David L. Goldfein speaks during Air Combat Command's change of command ceremony at Joint Base Langley-Eustis, Va., March 10, 2017. Gen. James M. Holmes assumed command from Gen. Herbert “Hawk” Carlisle, who retired after 39 years of service to the Air Force. (U.S. Air Force photo/Senior Airman Kimberly Nagle)