Pack only what you'll need while you're in transit, and things you'd need in case of an emergency. Pack light -- you'll have your hands full enough already!
Because restrictions on carry-on items change often, it's important to consult an official source or your airline before traveling. The TSA (Transportation Security Administration) maintains this page detailing permissible and prohibited items.
Make a list of the things you would normally use during the time frame of your flight:
Then plan for emergencies.
Make sure each parent has a "supply kit" in case you have to split up. One easy way to do that is to pack two smaller bags within a larger carryon. On the plane, you can each take a small bag to put under the seat, while the large bag goes overhead. Yet, everything is consolidated before and after the flight so that you're not juggling too many bags.
