Do you have to pay for your one year old's airfare?

Children under age 2 are able to fly on domestic airplane at no cost if they sit in the lap of an adult ticket holder.

On international flights, children under age 2 are required minimally to pay airport taxes and fees if they sit on the lap of an adult ticket holder. Some airlines also charge a minimal fee for the child's ticket - but it is substantially less than an adult fare.

If children under age 2 have their own seat on an airplane, they are required to pay for a ticket.