The TR3, also known as the TR-3B, is a rumored advanced aircraft often associated with UFO sightings and black projects within the United States. It is said to be a triangular-shaped craft that utilizes anti-gravity technology, allowing for high-speed travel and maneuverability. Proponents of the TR3 theory suggest that it is part of a secret military program, potentially developed by NASA or the U.S. Air Force. However, there is no official confirmation of its existence, and many consider it a product of conspiracy theories rather than verified technology.