Flying With Infants, Kids, or Pets: What to Book and When

Flying with an infant is easier than most first-time parents expect — but the booking rules are genuinely different from booking for an adult, and the moment to get them right is at the time of booking, not at the gate.

This guide covers infant fares, lap versus seat travel, bassinets, documentation, and what to sort out before you pay. Kids and pets are covered further down.

The short answer

An infant under two can usually travel on an adult's lap without a ticket of their own — but they must still be added to the booking, not simply carried on. On international flights expect to pay roughly 10% of the adult fare plus taxes. If you want the infant in their own seat, you must buy a ticket and bring an approved child restraint.

For long-haul flights, request a bassinet at the time of booking. They are limited, they sit in specific seats, and they are the single biggest difference between a manageable flight and a miserable one.

Infant flight rules: what actually applies

Lap infants

• Age: typically under 24 months at the time of travel.
• One lap infant per adult. Two adults can each carry one. Twins with one adult generally require a purchased seat or a second adult.
• They need to be on the booking. This is the most common mistake. A lap infant is not simply carried on — they are added to the reservation and appear on the manifest.
• The fare: often free or a small fee on domestic flights; on international routes usually around 10% of the adult fare plus applicable taxes.
• No separate baggage allowance on most carriers, though a stroller and car seat are commonly carried free or gate-checked.

Infants in their own seat

Buying a seat for an infant is a genuine option and, on a long flight, frequently worth the cost. Practical points:

• You must buy a ticket at the child fare for the seat.
• The infant must use an approved child restraint — a car seat certified for aircraft use. Not all car seats qualify, and the airline will check.
• The seat must be a window seat on most airlines, because a restraint in an aisle seat blocks evacuation.
• You get the infant's own baggage allowance and, on some fares, frequent flyer credit.

Minimum ages

Airlines set minimum ages for flying, and they differ for domestic and international travel:

• Domestic: commonly 7 days old, sometimes 2 days.
• International: commonly 14 days, occasionally longer.
• Premature infants: may face a longer restriction — often calculated from the original due date rather than the birth date.
• A medical clearance letter is sometimes required for very young infants.

Confirm the specific rule with your airline rather than assuming, particularly if the baby is under a month old.

Booking flights with a newborn: the practical decisions

1. Decide lap or seat early. It affects the fare you are quoted and the seat map you need. On a flight over about four hours, a seat is usually worth it.
2. Request a bassinet when you book. Available on some long-haul aircraft only, limited in number, and assigned to specific bulkhead seats. Waiting until check-in usually means they are gone.
3. Pick your seats deliberately. Bulkhead rows have more floor space for a car seat or for a crawling infant, but have no underseat storage. Near the lavatory means noise and foot traffic — avoid it.
4. Book a flight timed for sleep where possible. A departure that coincides with the baby's sleep window makes the whole journey easier, particularly overnight on long-haul.
5. Check the baggage rules for baby items. Strollers and car seats are usually free or gate-checked, but the rules vary and a large stroller may need to be checked at the counter rather than the gate.
6. Add the infant before you pay, not afterwards. Adding an infant to an existing booking is sometimes possible but rarely straightforward, and fare rules can change.

Documentation for infants

• A birth certificate is commonly required as proof of age, particularly for a lap infant whose fare depends on it — and some countries require it on arrival regardless of age.
• A passport is required for international travel, including for infants. Apply early; infant passports usually need both parents present or documented consent.
• A visa may be required for the infant depending on nationality and destination — do not assume an infant travels visa-free because you do.
• Consent documentation if travelling with one parent, or with neither. Some countries require a letter from the absent parent, sometimes notarised, and airlines can refuse boarding without it.

The consent point catches people out more than any other. If you are flying internationally with a child and the other parent is not travelling, check the destination's requirement in advance.

Booking flights with older children

• Children aged two and over need their own seat and ticket, at the child fare.
• Seating together is not guaranteed on every fare. Several airlines now commit to seating young children beside an accompanying adult, but Basic Economy fares frequently assign seats only at check-in. Select seats at booking if sitting together matters.
• Unaccompanied minors — children travelling alone — require the airline's unaccompanied minor service, which usually cannot be booked online. See our family flight booking guide for the age rules and how to arrange it.
• Child fares are not always cheaper than adult fares on sale. Compare, rather than assuming.

Booking flights with pets

Pets are a genuinely different process from children, with their own limits:

• In-cabin travel usually requires an approved carrier that fits under the seat, within a combined pet-plus-carrier weight limit that differs by airline.
• Cabin pet spots are strictly capped per flight and fill quickly. Book the pet at the same time as your own ticket.
• Breed restrictions apply to short-nosed breeds on cargo transport, and sometimes in the cabin. Confirm your breed's status before booking.
• A separate fee applies, charged each way and separately from your ticket.
• International travel adds the destination country's import requirements — which can include quarantine, microchipping, and paperwork that takes months.

If you are travelling with a pet rather than a child, our guide on pet-friendly airline policies covers the comparison between carriers in more detail.

Frequently Asked Questions

Do infants need their own ticket to fly?

A lap infant does not need a seat but must be added to the booking — they are not simply carried on. If you want the infant in their own seat with an approved child restraint, you must buy a ticket for them.

How much does an infant flight cost?

On domestic flights a lap infant is often free or carries a small fee. On international routes, expect roughly 10% of the adult fare plus taxes. A seat for an infant is charged at the child fare.

How old does a baby have to be to fly?

Commonly seven days old for domestic flights and fourteen days for international, though it varies by airline. Premature infants may face longer restrictions calculated from the original due date. Confirm with your specific carrier.

Can I fly with a newborn?

Usually yes, once past the airline's minimum age — typically a week for domestic travel and two weeks for international. Some airlines require a medical clearance letter for very young infants, so check before booking.

Can I bring a car seat on a plane for my infant?

Yes, if the seat is certified for aircraft use and you have bought a ticket for the infant. It must normally be placed in a window seat, because a restraint in an aisle seat blocks evacuation. Not all car seats qualify — check the certification label.

How do I get a bassinet on a long flight?

Request it when you book, not at check-in. Bassinets are available on some long-haul aircraft only, are limited in number, and are assigned to specific bulkhead seats. They are usually offered on a first-come basis by booking date.

Do I need a birth certificate for a lap infant?

Often yes — as proof of age, since the lap infant fare depends on it. Some countries also require a birth certificate on arrival regardless of the child's age. Bring the original rather than a photocopy.

Can one adult fly with two infants?

Generally not on laps — most airlines allow one lap infant per adult. With twins you would typically need a second adult, or to buy a seat for one infant and use an approved child restraint.

What documentation is needed to fly internationally with a child?

A passport for the child, and often a visa depending on nationality and destination. If only one parent is travelling, or neither, some countries require a notarised consent letter from the absent parent — and airlines can refuse boarding without it. Check the destination's rule before you book.