Fast for fifty years ago, maybe. I wish they’d tell us about the cool stuff they built in the 80s or 90s.
Look at the defense allocations for basic research into hypersonic capable materials to prove that they are still years away the most basic deployment and once the research is done, there is no supply base to make the materials (FA8650-20-S-5003)
How many aircraft today can fly horizontally over 2,000 mph?
". . . maybe."
It may have been fast 50 years ago?