What airline did you use?

Thank you all.  I wound up booking with AA.  I appreciate all of the advice and insights.  It's definitely made me feel better.  Hopefully this is the last time I have to worry about this.  

That was my fear! Surgery I was cool with, flying and 'fitting' into a seat i was scared about. I had a bmi around 70. I flew southwest. I bought the extra seat. Three seats are side by side on either side of the plane. My husband had the aisle seat, empty seat in the middle and I had the window. I sent an email to Southwest asking about their customer of size policy. I actually received a call from them the next day and they told me if needed, they could have a plus size wheel chair ready if walking was too much, I could preboard and pick the seat I wanted (no additional cost).

I bought the cheapest tickets with southwest, bought the extra seat (which they will refund you) and got to preboard as well. The seats are that comfortable BUT having that leg room and extra seat was amazing. I had a GREAT experience flying and actually got to enjoy the flight. Who knew?! :)