H.H.
That is quite a long trip with little ones, I don't envy you at all! I just started selling a product on my website that you may find useful as it's suggested as use in the car or on planes. It's called the Snack & Play Travel Tray and you can buy it at http://www.azactivekids.com for $19.99.
No pressure, but they're nice to use when traveling with small children because it attaches right to their lap so your not having to use the little fold down tray (that's often not close enough to them, not large enough for what they're doing, stuff falls off, they bang it and annoy the people in front of them, etc.). The nice thing is it's also light weight and easy to carry on your shoulder with the strap. If you're interested, go to the website to email me. Thanks,