Unless you are certain you can clean utensils, opt for disposables. Airline meals may not appeal to all children. Air travel tends to dehydrate people. Drink plenty of water. Women who are nursing need to consume more fluids.
Children often have trouble with pressure changes at takeoff and landing.
If you call ahead, some restaurants may be able to prepare special kids meals. Encourage children to eat normally, but realize that a 'poor' diet won't hurt for a few days. Check food for safety. Check with them. Remember to ask airlines, train or bus companies and hotels for guidance and assistance.