We have two children with autism and travel to Florida from Ireland most years. The flight is usually 7 hours to Newark then about 2 1/2 hours from there down to Orlando. Initially I was very worried - particularly on the 7 hour international leg that one or both of them would have a meltdown, but we did as much preparation as possible and so far seem to have survived.
DS who was 7 on his last trip loves planes and has no problem flying. We chose Continental as our airline last year as they had seat back TV's which kept him amused for most of the leg from Dublin to Newark. I also had loads of homemade word searches which were relevant to him (names of dinosaurs, names of horses where he goes riding etc.,) and things he likes doing.
DD who was 6 was more of a problem as she (like me) suffers from travel sickness and also has a short attention span. I again brought her loads of sticker books and other stuff to keep her amused and this year we are taking an MP3 player with all her favorite songs on (she is really into music)
Another tip for us is to bring food they will eat as neither of them will eat airline food - I made sure we had plenty of snacks and we managed to get something to eat while waiting for our connecting flight in Newark.
It is not so bad on the way home as the Newark - Dublin leg takes off at 8:15pm and lands at 2am so DD usually falls asleep / unfortunately DS doesn't sleep but plays the game system on the seat back TV's all the way home.
Our journey can take 17 hours door to door but we love WDW and for us it is a special place and a chance where we can be like a "normal" family. We love it so much we have bought into DVC and our kids know they will come back year after year.
Go for it and have a grea time
