1. my experience is that the worst way to start/end a trip is to drive in LA traffic to the airport. if you live in LA, use LAX (even though it's horrible). the last thing you want is to go to SNA in traffic for 2+ hours on the 405. it's demoralizing and potentially creates unnecessary anxiety.

2. price out three or four hypothetical trips and make sure that the options are about the same in terms of price/connections to your preferred destinations.

3. all other things equal, go with AA for the reasons others have mentioned.

we fly AA to dallas and the east coast and use US Air for PHX flights.