U.S. Air Force Senior Master Sgt. Jeffrey Zimmerman, 78th Aircraft Maintenance Unit superintendent, gives U.S. Air Force Gen. Herbert “Hawk” Carlisle, commander of Air Combat Command, the thumbs-up during Carlisle’s final flight at Joint Base Langley-Eustis, Va., March 9, 2017.Carlisle commanded ACC during the historic announcement of the F-35A Lightning II and its initial operating capability. (U.S. Air Force photo/Staff Sgt. Natasha Stannard)