U-2
Look, nobody is going to fly a U-2 at an altitude low enough for any markings to be identified from the ground. It would be as obvious as sailing a nuclear missile submarine on the surface off the coast of the U.S.S.R. I'm not even sure the plane works that well at those altitudes, and maneuverability is not a strong suit.
This, and a number of other things, make me doubt the authenticity and/or accuracy of these "memos."