The UFOs do not seem to exist as tangible, manufactured objects. They do not conform to the accepted natural laws of our environment. They seem to be nothing more than transmogrifications tailoring themselves to our ability to understand. The thousands of contacts with the entities indicates that they are liars and put-on artists, the UFO manifestations seem to be, by and large, merely minor variations of the age-old demonological phenomenon.
John A. Keel (1970). “UFO's: Operation Trojan Horse”