I'm not a mom but had the "opportunity" to fly with friends' kids and neices enough to help out a little. Not all of this answers your questions, its just some stuff I picked up along the way:
1) Take their shoes off on the flight. They wont kick the seat in front of them as much if it hurts.
2) Let them sleep whenever they want to sleep. Worry about the time change when you get there. Better to have a temper-tantrum in the privacy of your hotel or house than on an airplane.
3) Get a portable DVD player, lots of DVDs, and buy extra battery packs! If you run out of batteries, you'll be hurtin. If you have more than one kid, either have more than one player or make sure there is more than one headphone jack, and bring DVDs they both like so you dont have the "which one do we watch now?" fight on the plane.
4) If you do have more than one kid, try to get more than one window seat. I think my neices honestly thought the aisle seat wasnt going to Disneyland.
5) Buy some little airplane trinkets from a store - like a mini plane, or some wings, pens, coloring books, etc. Give them to the steward(ess) and have them "presented" to your kids for good behavior every couple hours throughout the flight. When we were little, the plane used to give this stuff out, but now its bring-your-own bribary! And it works...
6) Worry about the time change slowly. No need to do it all in one day. Let them sleep right when you get there, but then adjust an hour or two each day. No big deal if your kid is still falling asleep at 4pm a week after you arrive, at least they wont be insane. Then just keep them up a little later each day. Sugar works!
7) Definitely help them understand time difference and sunrise/sunset. An orange for the sun and a tennis ball for the earth works. If they know whats going on, it will be more of a fascination than an annoyance. Talk to them about how they feel so that they will understand that its ok to be sleepy when its light out and awake when its dark, then they may not react as grumpy.
8) Game Boys, coloring books, post cards to write and mail when you arrive, snacks, and a pillow are good too.
9) Encourage them to walk around the flight, then they wont get restless. Take them to the back and do some stretches with them every couple of hours - toe touches, arm stretches, etc. If they are small, they can do a bunch of jumping jacks or something. Anything to get out a little energy will help.
10) Time consuming projects are good too. Something they can learn. Like a magic trick kit, oragami, or that thing where you use a string and make different patterns. Book stores have lots of things like that.
Thats all I can think of at the moment. Good luck!!
