He makes a face whens he mentions these machines and contraptions used for flying-- that's not real flying. That's not the same, not what he meant at all.

"No, it isn't. I mean flying, by your own power and volition."

There is nothing in the universe quite like flying. Sure, it tended to make any human passengers a little ill, but they simply can't appreciate it like an angel can. He doesn't fly as well as he used to-- not since the Fall and the years in Hell-- but he still can, and does, to what limited extent he's allowed to here.

"I could take you with me. It's a simple enough thing."