Thank you very much for your reply! (Especially since it was a dumb question, as I now realize.) Understood, flying had survival value after Chicxulub. I was wondering about the "mechanism(s)" -- like maybe they could travel farther and faster to find food than creatures walking on foot, with food being hugely limited then?

I really enjoyed your piece!

(When I was 7, I had little plastic dinosaurs. I cut a cape out of paper, put it around the neck of the archaeopteryx, called it Super Reptile, and wrote and illustrated a couple "books" about it's adventures.)

Thanks again!