A lighted object seen at night by several people was found to have been a plastic hot-air balloon.
It was reported to the CU project that several persons at Castle Rock had seen an illuminated transparent object drifting over the town about 6:00 p.m. Mainly because the principal witness insisted that the object appeared to be about 75 ft. long, project investigators went to the scene.
The principal witness, interviewed the following evening, reported that, while he was outdoors in the early evening, he noticed several lights in the sky that were focussed toward him. He made out a transparent object about 75 ft. long by 20 ft. wide. In a circle underneath it were about twelve lights; he judged them to be much brighter than car headlights, though they did not blind him. He estimated the object to be about 25 ft. above the ground, which it illuminated. The object appeared empty; he could see through it. At first it was stationary; then it began to drift northward over the town. He followed in his truck, stopping at a service station to tell the men there of the "flying saucer." They later reported having seen slow-moving lights that dropped several fiery objects as they disappeared north of the town.
The investigators then visited the owner of the service station, and while there heard a radio report that a local teenage boy had launched a plastic hot-air balloon at about the time of the sighting, from a location about a block upwind of the principal witness' location. They learned by further inquiry that the balloon had been a polyethylene
suit bag about two by three feet, with balsa cross-members supporting six small candles and a cup of lighter fluid. Several persons at the launching saw the balloon drift over the principal witness' location.
The investigators concluded that the object of the sighting reports had been the balloon, despite the witness' exaggerated estimate of its dimensions.