Q. How do I book a flight for my two sons, ages 10 months and 4 years. Are the prices the same?

A. For domestic travel, you don't need to buy a seat or pay anything extra for your younger son, although it's much safer to buy a seat for your toddler and strap him into an approved child seat, rather than to hold him during the flight. In most cases you'll have to pay a full fare for four year old, since he's occupying a seat that the airline could otherwise sell to an adult. On international flights, even toddlers are charged, usually 10 percent of the applicable adult fare.