Tentatively, I am inclined to think that all of those and more could be part of the phenomenon. And, as Jacques Valle concluded, there is an element of deception about the whole thing that suggests great intelligence, discipline, and potentially malevolent purpose.
Before I fell asleep wit hthe TV on last night, I was watching a Ancient Aliens show that said that the entire “Close Encounters of the Third Kind” was an exact reenactment of an actual UFO landing at Holloman AFB.
According to the story, a UFO landed at the base and was filmed on 16mm, a copy of which was given to Steven Spielberg - that’s all I remember.