Thanks. I didn't really understand weightlessness until this made me think about it. If I stood on a normal weighing scales, falling vertically feet first, the scales would show my weight when at terminal velocity, because the force of the air on the bottom of the scales would equal my acceleration under gravity. And the same force would be transmitted to me by the scales. Then if we take away the scales, the air below me is acting on me the same way as the ground normally does. Same in the indoor wind tunnel where the air is moving up instead of me moving down, I'm still at terminal velocity there.

If I was free falling in a vacuum, or somewhere that the air was being accelerated at the same rate as my fall (like a space station or a vomit comet), there would be no such force, the scales would read zero, and I'd experience what they call weightlessness.

Is that all correct?

Yes.