The mysterious flying object that one man saw looked like a 40-foot-long Tic Tac" and was maneuvering and shifting directions rapidly. That claim ... comes from retired Cmdr. David Fravor and bears the Pentagon's stamp of approval. And it was one of many confounding examples of unidentified flying objects the Pentagon investigated in the Advanced Aviation Threat Identification Program. "There is very compelling evidence that we may not be alone," Luis Elizondo, a former Pentagon official, told CNN. The belief in alien encounters has long been a prominent feature of American life. A 1997 poll ... found that 80% of Americans think the government is hiding knowledge of the existence of extraterrestrial life forms. Many of the best known alien claims come from Project Blue Book, the name for the US government program tasked with investigating reports of UFOs from 1948 to 1969. In that time, Air Force personnel looked at 12,618 reported UFO sightings and said that 701 remain "unidentified." In 2010, seven former US Air Force personnel described their personal encounters with UFO sightings over nuclear weapons facilities in incidents in the 1960s, '70s, and '80s. Three of the former Air Force officers said UFOs hovered over nuclear missile silos around Montana's Malmstrom Air Force Base in 1967, causing problems with the military base. Former Air Force Capt. Robert Salas said one of his guards told him about a red, glowing object about 30 feet in diameter hovering above the front gate.