Pack a spare outfit for everyone. Dd spilt a can of Coke over herself and DH on a 6 hour flight once.
For the flight, an iPad or something with games or films on. I let my Dd pick a few bits at the airport before we board, an overpriced magazine, some sweets to help with the pressure and their ears.
If you have another adult flying with you, pack a small hand luggage case with enough stuff for overnight just in case your stuff goes missing.
Don't worry too much about bedtime. Dd is either shattered from swimming all day or if she's over excited and can't sleep, we put a film on the iPad for her to watch as she falls asleep.
We always prefer to go for a proper meal in the terminal before we board, then if the plane food isn't up to much, no one is going to starve!
Pack some cheap inflatables if they are the kind of thing your boys like. Most hotels sell them for £££. Or water pistols, they seemed popular last time we went away.
Very jealous, I can't wait to get back on a plane.