An oft reported UFO shape is the triangle, a ship that looks a bit like a fat boomerang. This is not only an aerodynamic shape, amenable to travel within an airspace, the shape also supports gliding. What the shape does not support is anti-gravity, the ability of a ship to evade the Earth's gravity by creating its own gravitational field. Triangular UFO's are therefore not alien, but are simply a type of airship produced by the US government, in secret. Why the secrecy, and why are these ships so often mistaken for UFOs? This is the point, as though they were constructed to be another stealth plane, their ability to hover, pointing their jets downward, allows them to be mistaken for space ships that have anti-gravity capabilities.
Triangular UFO are being seen worldwide at this time, to build a debunking case against all the mass sightings also occurring worldwide, in case this debunking should be deemed necessary to stop a panic over the alien presence. Should such a panic occur, the US military would hold a press conference and unveil the new stealth plane, whereupon the media would announce with great fanfare that UFO's have been explained away! To prepare for such a debunking, these stealth planes are sent forth to coincide either with a sighting or slightly after. Media coverage of any mass sighting invariably includes either speculation that the UFO was this familiar triangle shape or statements to this effect. In matters of this cover-up, they've got themselves covered!