SouthWest?
Be in the front when they call you group if ya want a good seat (if they still do that).
Other than that, I will never fly with them again. They are 3 for 3 on losing luggage. (first mine (when I was still in the Army and it was my duffel bag no less , then my wife's, and then my friend's wife's) Maybe it was because we were all going to Vegas together
Then again, it could be the caliber of people they hire.
Since then, my wife and I have refused to check on luggage, no matter where we go. If it doesn't fit in a carry-on, it doesn't go. I also ship stuff to myself that is now taboo for carry-on (contact solution, shampoo, etc) the day before I leave. It's worth the UPS charge for the non-hassle of the check-on luggage rituals. We get off the plane and go. Usually there is a package waiting for us at the hotel, already.
As for clothes, most hotels have laundry service and, if not, there is always a laundromat nearby.