It's actually interesting how not secret most of those projects actually were. President Johnson couldn't resist blabbing about the SR-71 in 1964, only one yea

It's actually interesting how not secret most of those projects actually were. President Johnson couldn't resist blabbing about the SR-71 in 1964, only one year after A-12 operations had begun and 2 years before SR-71 operations began. The U-2 began operations in 1957 and was revealed to the world, along with the equally secret mission of overflying the Soviet Union, in the Gary Powers incident in 1962. The F-117 was introduced in 1983 and was revealed in 1988. It's possible that there are additional still secret projects that operated out of Groom Lake, but I find it interesting that most of the super secret projects there were only completely secret for a period of a few years.