Cabowser, your son sounds very similar to mine. Luke is 6 and he too uses alot of scripting, but in the last year or so it's starting to be replaced by his own sentences. As his understanding of the words increases, he uses the TV/film/book sentences more and more appropriately, til now he only uses them when he can't think of how to say it, but knows it's something like....
We have taken my son (and his younger brother) to WDW twice now, and we have a 9 hour flight each way. Some of the points others have made are really useful. I found a book about some kids travelling on a plane very helpful, as would a social story be.
Last time we flew over, in December, Luke was occupied most of the time with his CD player (playing Disnay songs, of course!), some colouring books and some sticker books. I also have to take loads of snacks for him, and drinks, because he won't eat airpane food. He did have an hour where he went to the toilet about 30 times (in-out, in- out), but as there was no queue and we were right next to it, I just had to let him get on with it
We always tell the airline before-hand, and ask for seats at the front, as Luke too is a kicker. So far we have always been lucky, and been given them, but if for whatever reason we didn't, we are always prepared to sit with one of us in front, so at least he would just be kicking me or my husband. The airline also always lets us pre-board, which saves a great deal of hassle, and means he can get settled before everyone else starts milling around.
I have to say Luke loves flying. He loves take-off and land, and watching the other planes at the airport, which is just as well as obviously he can't have his CD player during take-off and landing. He also likes the enclosed nature of his seat, we put him by the window with one of us next to him, and he snuggles right down.
The only real problems we have had have been when he has been asleep at night on the way home, and we have had to put his belt on because of turbulence. This happened when he was about 3, and he was asleep on my lap, so I had to move him. Well he went ballistic, and refused to be strapped in. Lesson learnt ; make sure he is strapped in BEFORE he falls asleep, LOL!
One more thing to add, just to echo what someone said above. Our children might act in a way that we think is annoying to other people, and whilst I try to keep this to a minimum, at the end of the day they can't help it. There are thousands of people out there who behave anti-socially on planes every day, with no excuse, and most people tolerate them with no complaints. I'm sure you do. The worst flight I ever had was a charter flight back from Spain loaded with moaning shouting badly behaved children who were just tired, and people didn't care. My kids were like angels compared to them, and that is saying something. Don't feel worried if you get any comments or looks, (and I rarely do) remember people don't know the half of it, and if they did they would give you a medal not a dirty look!
You will have a great time! My current worry is how to explain to my son that we are not going back til next February. Every morning he gets up, puts a load of DVDs in a suitcase, and sings "Aeroplane, aeroplane, areoplane,aeroplane, we're going to go to Disney!". I have to say "No it's school today"

. But he did make that song up himself!
