mrflash818 sends word that the CIA has taken the blame for a majority of early UFO sightings. In a tweet, the agency said, "It was us," and linked to a document summarizing their use of U-2 spy planes from 1954-1974 (PDF). "High-altitude testing of the U-2led to an unexpected side effect — a tremendous increase in reports of unidentified flying objects," the CIA wrote in the document, which it wrote in 1998. "In the mid-1950s, most commercial airliners flew at altitudes between 10,000 and 20,000 feet and [many] military aircraftoperated at altitudes below 40,000 feet. Consequently, once U-2s started flying at altitudes above 60,000 feet, air-traffic controllers began receiving increasing numbers of UFO reports." [T]he CIA cross-referenced UFO sightings to U-2 flight logs. "This enabled the investigators to eliminate the majority of the UFO reports," the CIA wrote, "although they could not reveal to the letter writers the true cause of the UFO sightings."