A series of triangular UFOs were reported on the skies of Belgium between 1989-1990. They were chased down by F-16 jets and photographs were taken. They were suspected to be a stealth F117 using the Belgian highways as a flight path.
Mass sighting of large, silent, low-flying black triangles in Ans, Wallonia, which were tracked by multiple NATO radar and jet interceptors, and investigated by Belgium's military. Photographic evidence exists. One close encounter was reported.