Just ask a flight attendant for help as soon as possible. Tell younger children to stay seated after the plane lands. A flight attendant will help them in a few minutes. If your child is older, tell him that if the plane gets rerouted and ends up in an unexpected location, he should contact airline personnel. Older kids may be inclined to leave the airport in search of food or lodging, but the airline will make these arrangements.
Some airlines allow parents to escort kids onto the plane before the flight.
If so, you can meet the people seated nearby, point to the lavatories, and explain how and when to use the flight attendant call button. Tell your child the plane will make noises in the air, like when the landing gear goes up and down and the wing flaps move. Sometimes the plane may feel like it's traveling on a bumpy road. The pilot suggests staying seated with the seat belt loosely fastened. Don't leave for home until the plane takes off.