Your carry on bag should be small and light The most important things for your trip(passport, airune tickets, travel insurance documents, credit cards, cell phone, keys, etc.) should go in your carry-on bag
You should bring a change of clothes in case your luggage is delayed
You should also take medicine you need in your carry-on bag
Bring snacks to eat on the plane Cookies. muts, and dried truit are good. Don't bring chocolate it's very messy For long trips, bring a sandwich. And don't bring water- you can't take it through security
You should buy some at the airport betore you board the plane. Remember to bring a good book or your tablet