I have to say everything here has been pretty right on, but I must stress it really depends on where your weight is and what airline/seat you pick.
I am a 26 with my widest part being my thighs/hips/bum. I've flown Southwest, Airtran and US Airways while being this size. I have been eye balled a few times cuz I just about don't make the arm rest down rule. However, on most planes I make the seatbelt without the extender. I found Airtran had the longest seat belts while US Airways had the shortest. My hubby is a big and tall guy with the usual belly so he always needs the extender. The extenders are those demonstration belts the flight attendants use during the pre-flight safety announcements to explain the locking mechanism. Sometimes if they have extra we get one when we sit, other times the flight attendant hands it off as they walk past after the demo. Personally I always thought it was handled discreetly, even when we have to ask or have been asked if we wanted one. (Some have been mind readers and we just had to put our finger up and say 'excuse me...' and they offered it and hardly anyone would have seen the transaction)
On Southwest planes my husband finds that it's actually better to sit by the window as you get a little room from the curve of the plan to lean into whereas on the aisle you're always on guard to not get hit by someone walking by. USAirways really depends on the plane - I second the SeatGuru.com suggestion, that is a really helpful site. However, airlines have the option (and sometimes necessity) to substitute planes, so just because you book on a A321 doesn't mean you might not get a 767 on flight day. This happened to us on USAirways and our carefully picked out seats were thrown to wolves as the plane that showed up had a completely different coach configuration.
I am more familiar with Southwest policies regarding extra seats for 'people of size' and I think theirs is pretty fair. If you buy a second seat and the plane is not full, you can request a full refund of the second seat fare. Should be up on their website for the full rules, etc; but it would give piece of mind to buy the seat in advance. Depending on the price it might just be worth the extra money for the comfort
If we have to do another flight longer than 2 hours that's what we're doing. Depending on the itinerary, 3 seats on Southwest is cheaper than 2 First Class on USAirways. However, I believe if you call any of the airlines you can book and pay for a 2nd seat for yourself but they all have different policies regarding refunds and pricing, etc. (However, we have yet to actually book 2 seats for 1 person so I can't vouch for how easy the process is, all I can see if that you usually have to call since the website won't let you put in the same passenger information twice. you'd think they'd give a checkbox or something that says, 'i want 2 seats'
~ )
I don't know the rules for the arm rest during take off and landing, but we always put the armrest up between us as soon as we sit (easier to get the belts on) and noone has said anything. Only one time on a completely full Southwest flight did the attendant mention it since I had the other armrest between me and a little girl up while I did my seatbelt. I think she was concerned I'd try to take up the room on the little kid's seat too but I explained it was just while I got the seatbelt fastened. I got the lock clicked, put the arm down to show I could and she went on her merry way. On about 8 total short haul and long haul flights across the 3 airlines in the last 4 years, that's the only time I heard the arm rest thing mentioned at all. So it's an interesting little factoid to learn but seems to be only intermittently enforced.
I wish you luck. There seems to be some good suggestions on here (I like the lawn chair one) so hopefully this will ease some apprehensions. The #1 advice I can give is just relax
If someone makes a comment, ignore it, you are who you are at this moment and it can't be changed. I'm sure if you could snap your fingers and be a size 8 you would do it (I would!) but we can't so it's out of our control at this point in time. (for the future anything's possible
) If the airline makes a comment, just be prepared to defend why they are wrong (if they are) or pay for the extra seat and enjoy your vacation. I always make sure I have a reserve for unexpected annoyances, and this qualifies as one
I would agree that off-peak times to fly would be most likely to have the extra seating available so you wouldn't be cramped. For the life of me though I can't remember how full our last 7 am flight to FL was
. The 7am to Puerto Rico was empty enough we got a 3 seat row to ourselves, but I don't think that helps this situation
An earlier flight time would help if for some bizarre reason the flight is full
and they want you to buy the extra seat - you'd have more options for them to rebook a later flight same day for you.