Flying with children and infants

Carriers divide young passengers into infants, children and unaccompanied minors, and each carrier draws those lines where it chooses. The common pattern is that an infant is under two at the time of each flight and a child is under twelve, but the thresholds and the way they are applied to the return leg vary enough that you should read the airline's own family travel page for your specific carrier.

The age that counts is usually the age on the date of travel, not the date of booking. A child who turns two between the outbound and the return is a real and frequent problem: on many airlines that return leg needs a seat and a child fare, and the ticket has to reflect it from the start.

An infant travelling on an adult's lap is normally ticketed at a reduced fare or a percentage of the adult fare, plus taxes. It does not buy a seat, it does not buy a baggage allowance on most carriers, and it does not entitle the infant to a seatbelt of their own beyond the loop belt the crew provides.

Buying a seat for an infant costs more and, on most airlines, requires an approved child restraint device that you bring yourself. Parents who have done a long-haul flight both ways tend to have a strong opinion about which is worth it. The practical point for booking is that the two are different products and you have to choose at the time of booking, not at the airport.

• Lap infants are usually limited to one per adult, which shapes how a family of two adults and three small children can be ticketed at all.
• Bassinets on long-haul aircraft are limited in number, attach only at certain bulkhead rows, and carry a weight and length limit. They are requested, not reserved, and are confirmed by the airline.
• If you buy a seat for an infant, confirm the car seat's approval marking and its width against the seat before you fly. An unapproved seat is refused at the gate.

Several carriers now have a policy of seating young children with an accompanying adult without charge, and several apply it only if seats are available when the booking is made. In practice the reliable approach is to select seats at booking, verify them again after any schedule change, and check them once more at check-in, because an aircraft swap reassigns everyone.

If you are booking through us, tell us at the quote stage that you are travelling with children. Seat requests are made to the airline and the airline confirms them, so the earlier that request exists the better it tends to do.

Children need their own passport for international travel in essentially every case, and a child cannot travel on a parent's passport under the arrangements most countries now operate. Child passports also expire faster than adult ones, which catches families who checked the adult passports and assumed.

Some countries require documentary evidence of parental consent when a child travels with one parent, with a grandparent, or with anyone who is not a legal guardian, and border officers do ask. The requirement is set by the destination and sometimes by the country of departure. Check with the relevant embassy or the official government source for your route before you travel — we are not able to advise authoritatively on immigration requirements.

A child travelling without an adult is a separate service with its own rules, its own fee, and its own paperwork naming the adult who hands the child over and the adult who collects them. Many airlines will not accept an unaccompanied minor on an itinerary with a connection, and almost none will accept one where the connection involves a change of carrier or a self-transfer.

This is not a booking you should make on price. Establish which carriers will accept the child on the routing you need, and build the itinerary around that answer.