Amateur, nighttime footage of US navy NOSS satellite formations.  See the links provided for more information. This doesn’t explain all triangular UFO sightings, but clears up some of the mystery. The second clip might be Iridium satellites and not NOSS. "NOSS" is an unofficial acronym for the US navy's Naval Ocean Surveillance System. To an observer, the satellites appear to travel in gro More..ups of three, or sometimes two. Depending on one's location they may appear as a triangle, or as lights moving in a straight line.