This topic definitely did not go the way I thought it would. My wife prefers the window seat while I prefer the aisle. So when I book flights I try to book the side where there's only 2 seats. The best, in my opinion, are the emergency exit seats because of the extra room. But usually don't get them because someone else already snagged them or because the airlines have started charging extra for them.
As far as airlines go, because we fly primarily domestic or to the Caribbean, we usually fly either Delta (our first choice) or American Airlines. That's because we have affinity credit cards for both and can use miles to help control costs. Plus, we don't get charged for luggage. I see and hear from many people that I should consider Southwest. Those same people tell me, when I ask "Why?", because it's cheaper. For the routes we fly I don't see it. I have compared with Southwest and usually find that Delta or American are actually cheaper and not by just a little.
I will say one of the worst airline experiences I ever had was with AeroMexico. We were on our way to Cabo. And on each leg of the trip there and back I had to go to Customer Service to get my seat assignment. That's because they had me on their passenger list but with no seat assigned and the planes were already full. It meant that my wife and I never sat next to each other and there was always the chance I would be placed on the next available flight. I thought this was ridiculous since I had booked the flights 4 months in advance and I was the only one affected. My wife's seating, which was booked together with mine, was never in question. I had received 3 emails from them between when I booked and when we left notifying me of flight changes (times and seat assignment). If I can avoid them in the future I will. But that may not be possible since they are a Delta partner and we use Delta a lot.
:
