The faster and more classified of the 2 blackbird aircraft on display in Palmdale. The A-12. From what I’ve gathered, this craft flew top secret even 2 years before to the SR-71’s announcing, which took place in 1964. Even after the project was shut down in 1968 the A-12 remained in classified secrecy for decades later. This particular A-12 was not seen by the public eye until the 90’s. The estimated speed of the A-12 was mach 3.35 in comparison to the SR-71’s mach 3.2. Aside from that, this craft could operate at a higher max altitude than the SR-71 and was specifically built for the CIA and operated only by CIA pilots.
I am still stunned in amazement that these supersonic aircraft existed in the early 60’s..well over 10 years prior to my birth into the world!