Zaghetti was at the helm of a jet from Milan to London's Heathrow Airport on the evening of April 21, 1991, when a flying object streaked across his field of vision. "At once I said, 'look out, look out,' to my co-pilot, who looked out and saw what I had seen," Zaghetti wrote in his report. An investigation later ruled out a missile -- but never ruled anything in, either. The close encounter is one of many reported UFO sightings among 19 files that Britain's National Archives posted Monday to the Web. The new material covers UFO sightings between 1986 and 1992. While the 1,500-page batch of documents debunks a host of UFO sightings, others like Zaghetti's near-miss with a UFO remain unexplained. Some things in the newly released files were either unhinged or unverifiable. One correspondent tells the military he was shouted at by aliens while sleeping outdoors. Another writes in "with extraordinary news," saying the "legendary 'feathered serpents' " are waiting for permission to land on Earth. And one U.S. pilot's tale of being ordered to shoot down a UFO over eastern England, forwarded to the Ministry of Defense by a UFO enthusiast, was kept on file even though the military turned up no evidence of it in its official records.