The very best thing about Project Bluebook is that it was started in 1952, and Groom Lake (ie, Area 51) started up as a classified aircraft testing range in 1954. I'm betting they got the idea from the weather balloon that crashed in 1952.
So sometimes you get a conspiracy that EXISTS but works backward from the way the nutters think it does.
In this case, it was a conspiracy to hide aircraft testing with outlandish tales about aliens. The people who think they're wise to the Con were the exact people who carried out the wishes of the Con, and DID IT FOR FREE.
Also, if you do enough drugs, you'll eventually see the aliens.
If you do enough of the GOOD drugs, you may or may not see the aliens, but you won't care.
ALTERNATE THEORY: The loons are right, and it really IS all about aliens. In which case, they build the kind of spaceships that CRASH. WE can do that, and we're not even NEARLY a star-faring culture. We should demand better aliens. And maybe treat the ones we already HAVE to some primate "hospitality". Fuck those guys. Seriously.