The allegations are that these crafts are created at top-secret military bases like Area 51 in Nevada, by reverse engineering alien technology.
Although MUFON investigates the bizarre triangle sightings, it still urges caution.
Roger Marsh, MUFON director of communications, said: “Please remember that most UFO sightings can be explained as something natural or man-made.”
Scott Brando runs website ufoofinterest.org which exposes hoax UFO sightings.
He is sceptical any inexplicable sightings have been made.
MR Brando says most triangle UFOs can be explained as aircraft, military flares, Chinese lanterns or skydivers in formation.
He said: “About other similar sightings I’d like to see some reports by MUFON, however many formation of sky lanterns or the launch of skydivers.”