Something that caught my attention recently is a flawed interpretation of the Kenneth Arnold UFO report. If you look at the original report from 1947found here, with particular attention paid to the drawings at the bottom of the page: http://www.nicap.dabsol.co.uk/arnoldka.htm and compare that to the flying wing shown seven years later, with both seen here http://www.answers.com/topic/kenneth-arnold it is clear that the flying wing seen in 1952 is a far cry from the objects drawn in the original report. This evolution of memory was later used to sell books. It was also used to argue that he saw a fleet of nine USAF flying wings, which, much to my surprise, is an explanation for the sighting still being used today. At this point I think we're safe to assume that we didn't have a [still secret] fleet of flying wings in 1947.