Two NASA Blackbirds: the one on the top is a YF-12, the one on the bottom is the YF-12C/SR-71. See more: Did you know that NASA YF-12C was actually an SR-71 with a bogus A-12 tail number? credit Aerospace

Two NASA Blackbirds: the one on the top is a YF-12, the one on the bottom is the YF-12C/SR-71.

See more: Did you know that NASA YF-12C was actually an SR-71 with a bogus A-12 tail number?
credit Aerospace pic.twitter.com/XhfwYZ8LLL

— Chris Bolton (@CcibChris) September 3, 2023