In the United States and United Kingdom, a black project is, in the vernacular, a highly classified military/defense project, unacknowledged publicly by the government, military personnel, or defense contractors. Examples of U.S. military aircraft developed as black projects include the F-117 Nighthawk stealth attack aircraft and the B-2 Spirit stealth bomber, both of which were highly classified and denied as existing until ready to be announced to the public.
In the United States the formal term is Special access program (SAP).
A black site is a location where a black project takes place.
- B-2 Spirit stealth bomber
- Boeing Bird of Prey technology demonstrator
- F-117 Nighthawk stealth ground-attack aircraft
- KH-11 KENNAN reconnaissance satellite
- SR-71 Blackbird Mach 3.3 very high-altitude reconnaissance aircraft
- Lockheed CL-400 Suntan high-altitude, high-speed reconnaissance prototype
- Lockheed U-2 very high-altitude reconnaissance aircraft
- Lockheed Martin RQ-170 Sentinel
- Lockheed Martin Polecat unmanned aerial vehicle
- Northrop Tacit Blue
- Operation Cyclone
- RQ-3 Dark Star high altitude reconnaissance UAV
- Lockheed Sea Shadow (IX-529) experimental stealth US Navy ship
- Hughes Mining Barge CIA project, authorized by President Richard Nixon in 1974 to discover secrets from sunken Soviet sub K-129
Currently classified, but speculated
- SR-72 stealth reconnaissance UAV—the SR-72 was confirmed by Lockheed Martin in October 2013.
- Stealth Blimp Reconnaissance platform 
- Greenwald, Glenn. "Dangerous Travels". Dangeroustravel.blogspot.com. Retrieved 2013-09-09.
- "An SR-72 in the works?". Airforcetimes.com. Retrieved 2013-09-09.
- "Meet the SR-72". Lockheed Martin Corporation. Retrieved 2015-06-17.
- "Investigation Casts Light on the Mysterious Flying Black Triangle". space.com ARCHIVED. Retrieved 2013-09-09.
- "Mystery - Blimp". Fas.org. Retrieved 2013-09-09.
- "The stealth blimp dot com". Thestealthblimp.com. Retrieved 2013-09-09.