FILE PHOTO -- The last active-duty Air Force C-9 Nightingale left Ramstein Air Base, Germany, on Sept. 20 for retirement at the air museum at Andrews Air Force Base, Md. The twin-engine, T-tailed, medium-range, swept-wing jet aircraft was used primarily for Air Mobility Command aeromedical missions, as well as transporting high ranking government officials. (U.S. Air Force Photo)