Recently declassified documents from the U.S. Air Force reveal a Cold War-era plan to build a round, vertical take-off and landing aircraft that can only be described as a flying saucer. The disk-shaped craft was designed to reach a top speed of Mach 4 and reach a ceiling of over 100,000 feet, according to a recently blog post at the National Declassification Centre, an arm of the National Archive. Read more