Triangular UFO sighted in Casper Wyoming

Summary

A 1966 report describes the sighting of a triangular object in Casper, Wyoming. A witness observed it through binoculars and described it as plastic-like, silent, and without exhaust. The object was moving slowly toward the southwest. An air traffic controller and an off-duty police officer also confirmed the sighting. Although a balloon was considered, there was not enough evidence for a definitive conclusion.