The Air Force has a history of FLAs, from the F-117 to the B-2. Now Fox News has an article about declassified plans for Air Force aircraft that looks like a flying saucer. I've always figured that any actual "UFO" sightings in the US were really prototypes of various military aircraft being tested. I doubt that these "Flying saucers" were ever built, but this article just reinforces my belief that most UFO sightings are hoaxes or test aircraft. This doesn't mean that Aliens aren't out there (for a serious, well thought out discussion of Aliens and possible invasion may I suggest Alien Invasion by Travis S. Taylor and Bob Boan), but I don't think they've made contact... yet.