Sorry for not replying to your post sooner, I've only just noticed it!
Anyway, well done for getting back out into civilisation, and having a go at flying, it can be daunting at first, but when you've done it a couple of times, you'll get to know the procedures.
Now, when you booked your ticket, did you tell the airline to note you were in a wheelchair? It's not essential, but if anything does go drastically wrong, at least you can say you informed the airline you were in a wheelchair when you booked the ticket.
You should also check the airlines lifting policy, as if you have trouble transfering, some airlines will not help, but the baggage people will usually give you a hand if you get stuck.
Regarding escalators, all airports will have lifts, so this is not anything to worry about, just ask staff where they are.
When you get to the airport, get there a bit early, as it's easier to check-in, also, there are usually porters to help with your baggage, just give them a couple of bucks to get your bags to the Special Needs counter.
Most major airports have these counters, they will help you with your baggage, and through check-in, they will also arrange for an isle wheelchair to wheel you to your seat on the aircraft.
When you check in, tell the check-in assistant who issues your seat number that you cannot walk, and you need an isle wheelchair to get you to your seat. Also, enquire to see if you can get a bulkhead seat, as these have no seats in front of them, and have more room to move around and do pressure lifts.
If the check-in assistant will not issue a bulkhead seat, tell her you will not be able to get up to let other passengers in and out of their seats if they are by a window if you are on the isle, this usually does the trick.
Also, tell the checking in assistant that you need to stay in your wheelchair right upto the aircraft door, once you are on the isle wheelchair, your wheelchair will me put into the aircraft hold. Remember to get a baggage tag for your wheelchair with a barcode on it when checking in though.
Once you have your boarding cards, ask the check in assistant how much earlier you need to be at the boarding gate, this is usually 30mins before everyone else so you are put on first.
After checking in, you can go through security, they normally just pat you down, then you can go and read a book utill it's time to go to the gate. Don't drink too much though in the cafe, if anything, I always restrict my fluids before a flight as you obviously can't get to a toilet. Bearing this in mind, just before you go to the boarding gate, empty your legbag/bladder, or if you do intermittant catheterisation, put an indwelling catheter in for the journey and connect it to a leg bag before you leave home.
As soon as you get to the boarding gate, tell the assistant that you cannot walk, and you need pre flight boarding. Be sure to tell them you cannot walk, as it leaves not room in their minds of your abilities.
When you are at the aircraft door, after transfering into the isle wheelchair, remember to take your cusion to sit on in your aircraft seat if you need it. If you get to your aircraft seat, and it's an isle chair on the side of a window, ask the attendants if you can sit by the window, once again, mention that if you can't you will be unable to get up to let people in or out of their chairs. You could always ask if there is a bulkhead seat spare, sometimes they will let you go there at the last minute and move the other person you a normal seat.
You then just have to enjoy your flight untill you land.
After landing, everyone else leaves the plane, and you get off last, don't forget your cusion or your hand luggage. Ask the flight attendants to bring your wheelchair from the aircraft hold, and have it ready at the aircraft door for you to transfer into, this is usually not a problem.
Once in your chair, ask if someone can help you get your baggage and help push you. This may not be what you like as a T12, but it normally fast tracks you through passport control so you don't have to que!
Then, once you have your baggage, that's it really, at least thats all I can think of anyway.
I've just returned from New Zealand from the UK, and in total over six weeks I did 8 flights, so this is all still pretty fresh in my mind.
Where are you flying from and to?