CC...i work for british airline and go to U.S alot....as previous people have said, if you want to do longhaul then expect to wait a very long time to do it. Have a friend who has been with AA for 17yrs and is still not on longhaul.
I do know someone who works for Southwest and they seem very happy. You do work alot, but the benefits are pretty good(by U.S standards) and you can certainly get around the country. Having flown with them a few times, the crews all seemed very happy
and enjoying their jobs.
Anyway..hope you fund what you looking for.
Timmy