It was produced as the C-9A Nightingale for the United States Air Force, and the C-9B Skytrain II for the U.S. Navy and Marine Corps.

[3] Despite being officially retired, one C-9B, BuNo 161529, was seen as late as November 2020 being operated by the U.S. Air Force as an experimental sensor testbed.

Auxiliary fuel tanks were installed in the lower cargo hold to augment the aircraft's range to nearly 2,600 nautical miles (4,800 km) for overseas missions, along with the addition of tail mounted infrared scramblers to counter heat seeking missile threats in hostile environments.

[citation needed] The C-9B aircraft have provided cargo and passenger transportation as well as forward deployed air logistics support for the Navy and Marine Corps.

[11] Data from Encyclopedia of World Air Power[5]General characteristics Performance Avionics Related development Aircraft of comparable role, configuration, and era