Ethical is a really wide playing field. I would guess that most of what we call "ethical treatment" by airlines is because of a rigorously enforced PWA. Airlines are no different than any other major corporation, with the major exception of an educated work force that stands united.

Jet Blue is a perfect example. Nice product, good reputation with passengers, full of blue juice. They seem to think their stuff doesn't stink and they treated their pilots so poorly that they decided to unionize.