United States Department of Defense aerospace vehicle designation

Typical Vehicle Designation Stencil for a USAF aircraft. This one is on the port side of a T-33A under the canopy frame.

Joint Regulation 4120.15E: Designating and Naming Military Aerospace Vehicles is the current system for designating all aircraft, helicopters, rockets, missiles, spacecraft, and other aerial vehicles in military use by the United States Armed Forces.