I'll just point out, as an alternative view for those watching on, that most people with an interest in military aviation accept without question that all sightings of 'UFO's are, in fact, clandestine military aircraft.
The rule of thumb is that whatever you see flying now, is some 20-30 years behind the curve.
There is nothing interesting about area 51, except the fact that it is home to Lockheed's Skunk Works. They managed to not only produce and test the F-117 Nighthawk, but field it operationally before the general public had any idea it even existed.
It's interesting, then, that talk of UFOs tends to center around area 51.
A nice piece of circumstantial evidence is that UFO mania began in the '50s, which was right around when prototypes of the first generation of post-WWII next-generation aircraft would have been conducting initial tests.