Numerous documents from the Federal Bureau of Investigation (FBI) files detail witness accounts and official correspondence regarding observations of unidentified flying objects (UFOs) in the late 1940s and early 1950s. The reports describe various sightings across the United States and Canada, including details on object shape, speed, altitude, and the reliability of witnesses. The documents also show the FBI's handling of these reports, including their attempts to verify information and their interactions with other government agencies and the media.