Unidentified Flying Objects and Air Force Project Blue Book From 1947 to 1969, the Air Force investigated Unidentified Flying Objects under Project Blue Book. The project, headquartered at Wright-Patterson Air Force Base, Ohio, was terminated Dec. 17, 1969. Of a total of 12,618 sightings reported to Project Blue Book, 701 remained "unidentified." The decision to discontinue UFO investigations was based on an evaluation of a report prepared by... more...