Quoting from this article: http://www.ufoevidence.org/documents/doc473.htm
-30 groups of witnesses including police patrols
-observed for hours a strange triangular object nearly silent, maneuver- ing at low speed and very low altitude, without creating the least amount of turbulence.
At least 30 witnesses of slow moving and very quiet triangles (gliders?).
Two radar stations scanning a country side without prominent hills. Good weather. Investigators were aware of the possibility of false images.[/QUOTE]
Pilots are looking at radar images. Witnesses on the ground are looking at triangles. What ties radar images to the triangles? This...
The Belguim policemen observed both the F-16's and the Triangle. The question then becomes: are the Beguim police lying or conspiring? If so, then what were the pilots chasing?
I believe that the Belguin police are telling the truth. If so, then the Triangle and the radar images are linked.
If you want a terrestrial answer, then it has to be a very high tech air craft, probably an American fighter.