The Vietnam War saw its share of UFO activity in the 1960s. One close encounter, in 1968, involved the crew of an American patrol boat that reported two glowing circular craft following them. The crew aboard a second patrol boat later reported seeing the UFOs over the first boat and a flash of light, followed by an explosion that completely destroyed the boat. These Vietnam reports included close observation of the unknown aerial craft. Wartime UFO stories are recreated in ... History's Hangar 1: The UFO Files." The accounts are drawn from tens of thousands of UFO cases in the archives of the Mutual UFO Network, the world's largest UFO investigation group. Former Air Force intelligence officer, Capt. George Filer ... described a typical report that he'd receive: "You'd have an aircraft flying along, doing around 500 knots and a UFO comes alongside and does some barrel rolls around the aircraft and then flies off at three times the speed of one of the fastest jets we have in the Air Force. "I would be told this unofficially. People tell you a lot of things that they don't put in writing or sign their name to. There was always this part of UFOs that, if you got too interested, it could mess up your career. And this is true today even with commercial pilots. I've also heard from people serving in Afghanistan saying they've seen UFOs, and the Iranian news carries UFO reports pretty regularly."