Out of the list of potential airlines you listed, I’d say Mesa and Xjet are probably your top two. I was at Xjet a few years ago. The training there is probably the best you’ll get at a regional, unless it’s changed. Their contract is leap years ahead of Mesa’s. I hear that upgrade at Xjet is down to a couple years. Mesa has 20 new 175’s coming next year. Great group of pilots. Training is okay. Oh, and Mesa DOES NOT require or offer the dorky looking bus driver hat