TR3-B is a triangular antigravity plane.

I lived in Belgium from 1989 to 1997. In 1990 there was an incident with two triangular discs that was chased by Belgian Military. It was all on television, and the belgian pilots told us that the triangular plane could make manouvres that the F16 could not, and the triangular planes could make speeds up to 10000 km/h. About one year later there was a small notice in the Belgian Expat magazine The Bulletin that the triangular plane was not a UFO but instead a US airforce plane. It was the TR3-B.