huge difference in the glide ratio of SR-71 & U-2

Yep. Like the difference between a lead-covered high drag rock and a feather.

Well, in view of its speed, I doubt the SR-71 had high drag. I'd like
to hear what Mary Shafer has to say about that.

And "lead-covered...rock" seems to imply you think weight affects
glide ratio. It does not.

A U-2 constructed of lead would have the same glide ratio as one
constructed of balsa wood. It would glide faster, but just as far.

vince norris