I fly roughly half SW and half American out of Phoenix, skewing toward American in the last few years. There aren't any other airlines that will have as many options out of here. It used to be that SW won for price, schedule, and options far more often than not, but those days are gone. I prefer American and get main cabin extra when possible now. You get a good deal more leg room, and frankly, I'd rather pay for that than the possibility of a high A boarding number on SW. You choose your seats at booking, and main cabin extra costs more (variable amount, even per leg if you book round trip). Of course, flight fares are kind of unpredictable lately, and I'm not sure when you are flying, but I would price check American if I were you. I have actually had pretty good luck with the American customer service reps handling complicated issues - booking with bereavement rates, booking unaccompanied minors, linking what looks like unaccompanied minors to my reservations booked with points, you name it. I am not familiar with their customers of size policies, though. Hope the rest helps.