Unexplained Flying Objects (UFOs) In 1947, a rash of sightings of unexplained flying objects (UFOs) swept America. Although the newly formed U.S. Air Force was the primary investigator of these sightings, the FBI received many reports and worked for a time with the Air Force to investigate these matters. This release details the FBI's role in investigating such reports between 1947 and 1954. Some information in these documents may have been redacted for security purposes.