posted on May, 26 2003 @ 07:52 PM
I would think that it depends on how radical the technology is. I mean, it's almost certain that there are aircraft that were built a half of a
century ago that we don't know about. Why the secrecy after 50 years? It has to be the technology.
If I had to guess though, I would say that the military only unveils aircraft to the public when they already have another aircraft (or spacecraft)
that is at least a generation ahead of the unveiled vehicle.