Secretary Hagel speaks at the farewell ceremony for Secretary of the Air Force Donley Secretary of Defense Chuck Hagel speaks at the farewell ceremony for Secretary of the Air Force Michael B. Donley at Joint Base Andrews, Md., on June 21, 2013. Donley served as the 22nd and longest serving secretary in the history of the Air Force. SHARE: Download: Full Size (0.05 MB) Credit: VIRIN: 253170-R-YOY69-628.jpg Photo Gallery