Comics/magazines. You get a crap toy on the front(you can dump on the flight) and activities, plus they will be delighted with it. Don't give them anything too soon, they'll be distracted and excited enough for a while. When they start to fidgit, have something to pull out to amuse them.
We got each of ours sticker books (they were 5, 4 and 2 when we flew to Oz). They got a sticker for every half and hour they were good (sounds a lot, but they slept, watched films etc). And I had a wrapped up small present for 1st, 2nd and 3rd prize at the end of the flight. (Mine are quite competitive - worked a treat!)
We had a magnetic travel game of snakes and ladders which we played ALOT.
As for extra cushions and blankets when you get on and build them a comfy nest.
They'll probably be given an activity pack on take off (check the website, it should tell you).
I found that the adult pasta was a better meal option than the childrens menu for one of mine, so don't necessarily request a childrens meal, or ask them to substitute the main meal part of it.
I agree, it really won't be as bad as you expect it to be. (but good luck anyway!)