ANYONE SEE THE ARTICLE THAT A MOM USED A BABY POTTY IN THE AISLE OF A PLANE? SHE WAS EATEN ALIVE WITH ONLINE COMMENTS. We carried a potty in our SUV the first two weeks of training when she wouldn't relax to go on a big pulic toilet. haha. I wouldn't do it in public, but the back of my car - yes... so I can sort of relate. Especially when we went to an outdoor festival with pot-a-pottys.
My daughter has been "Fully" (less than a couple accidents a week) #1 for about 1 month and 80% trained on #2 for week. We leave in 6 days for a 11 day trip. I've been thinking about this topic a lot.
I think children often treat pull-ups as the parents do - we have referred to them as underwear since day 1 and parents can't allow themselves to be lax because of the security of the pull-up or the child will just pee in them. From my knowledge parents who potty train with heavy reliance on pull ups often make the process significantly longer - BUT I think a Disney trip (4th trip in 4 years next week so I know what I'm referring to) is a special circumstance. We use pull ups at night even though she's only wet in it 2X in the past month - she also wet 2x without one on and I was over it. I think I used all my patience on my first child and am just out this time around

. I was strict with my first - I never bought a pull up and took diapers away cold turkey - it actually was VERY EASY- BUT my 2nd is a different child, I am a different type mom, and I just feel what's best for us.
We won't use a pull-up for the flight assuming she has a regular morning and goes without fits/drama/and will go right before we board. I will monitor her intake (typically I don't restrict at all) but she isn't going to be allowed anything more than a cup or so of liquid before the last potty, and probably nothing but sips after. Our drive is only 3 hours to airport - and we will stop once and she will pee or we won't take off again. The flight is only 2.5 hours. I actually thought about taking a full size beach towel for her to sit on... but idk if that will happen. AS far as #2, she goes every night - dinner, right to bath, then right to potty. This is her time, and she doesn't go other times - it's just naturally happened this way. There's a chance this will fall to crap with our eating, sleeping, and where we are so we will see what happens. I will have 2-3 pull ups in our bag at all times - just incase something crazy happens - like getting sick. Not carrying them is just asking for issues. lol.
I would NOT put a pull up OVER underwear - if they have an accident you will still have a mess to clean up - smaller, but still a mess.
Question for others - what concerns should I have with a airplane bathroom? I've flown several times but never over a 4 hour flight, so I've always "held it."