I was shown a film while on active duty in the USAF probably in about 1965, not before Aug 1964. It was being called the YF-12 at the time. The aircraft is the one shown here-
https://en.wikipedia.org/wiki/Lockheed_YF-12 .
I was in training at Castle AFB, flying the B-52’ in raw Spring of 1964.
We were making touch and go landings at Edwards AFB and tower asked us to extend our downwind leg in order to “get a fighter on the ground.”
We extended and turned base when tower told us to.
When we turned onto final approach, we were behind a fast airplane that looked like a C-119 because of the twin vertical stabilizers. It was moving much faster than we were and, by the time we landed, it was out of sight, probably in a nearby hanger.....Later that month, Johnson disclosed the new “YF 12A!”