Last updated: October 30, 2026. Airline policies are taken from the airlines and the US Department of Transportation’s published information; fares were checked on Google Flights on October 30, 2026. Policies change, so confirm with your airline before you fly.
Short answer: book early, put the whole family on one reservation, and choose an airline that guarantees free family seating (Alaska, American, Frontier and JetBlue do for children 13 and under). Children under 2 can fly on a parent’s lap free within the US; internationally a lap infant usually costs about 10% of the adult fare plus taxes. Strollers and car seats are checked free on major US airlines, and formula, breast milk and baby food are allowed through security above the 3.4-ounce liquid limit.
What flying with kids costs
| Typical rule on major US airlines | |
|---|---|
| Lap infant (under 2), domestic | No fare; the infant must be added to the booking |
| Lap infant, international | About 10% of the adult fare plus taxes |
| Child with own seat | Usually the full adult fare |
| Stroller and car seat | Checked free, at the counter or the gate |
| Seats together | Guaranteed free for kids 13 and under at Alaska, American, Frontier and JetBlue; other airlines may charge seat fees on basic fares |
Sources: airline infant and family seating policies and the US DOT Airline Customer Service Dashboard, checked October 30, 2026. Details differ by airline and route.
Example: for a family of four flying Atlanta – New York in March 2027, the cheapest nonstop round trips we found were $201 per person on Frontier (about $804 in total) and $279 on Delta (about $1,116). Frontier guarantees seats together for young children, but charges for carry-on bags, so add those before you compare. Details in our Atlanta to New York guide and our baggage fee comparison.
Booking tips
- Book everyone on one reservation. Family seating guarantees usually only apply when the child and adult are on the same booking.
- Book early. Seats together and good flight times disappear first. In our tests, flights booked five weeks out were 29–48% cheaper than one week out.
- Choose nonstop flights and good times. One flight is easier than two with children. Morning flights are less likely to be delayed; overnight flights can work for long trips if your kids sleep well.
- Avoid basic economy on airlines without a family seating guarantee, unless you pay for seats.
- Add the infant to the booking before travel, and bring proof of age (a birth certificate or passport).
- Consider a seat for children under 2. The FAA recommends a child safety seat in its own seat as the safest option. You can bring an FAA-approved car seat on board if you buy a seat.
At the airport
- Security: children 12 and under usually keep their shoes on. Formula, breast milk, juice and baby food in reasonable quantities are allowed above the 3.4-ounce limit; tell the officer before screening.
- Family lanes: many airports have family or assistance lanes at security; ask staff.
- Stroller: use it to the gate and gate-check it; it comes back at the aircraft door or at baggage claim.
- Boarding: many airlines offer family pre-boarding for young children; check your airline’s policy.
On board: tips from flight attendants
- Takeoff and landing: feeding, a bottle or a pacifier helps babies with ear pressure; older children can chew or drink.
- Pack a small “in-flight” bag: snacks, a change of clothes for the child (and a shirt for you), wipes, diapers, headphones and a few new small toys.
- Download shows and games before the flight; Wi-Fi is not always available or free.
- Walk the aisle when the seat belt sign is off.
- Be friendly with the crew. They can help with warm water for bottles and tips on quieter moments to move around.
After you land
Book an airport transfer with child seats or a rental car with car seats in advance; taxis may not have them. Hotels with family rooms or an all-inclusive resort can make the stay easier; see our guide to cheap all-inclusive resorts for families.
FAQs
Do babies fly free?
Within the US, children under 2 can usually fly on a parent’s lap without a fare. On international flights, a lap infant typically costs about 10% of the adult fare plus taxes.
Will my family be seated together?
Alaska, American, Frontier and JetBlue guarantee free adjacent seating for children 13 and under with an accompanying adult on the same booking (when seats are available). On other airlines, choose seats when booking, which may cost extra on basic fares.
Can I bring formula and breast milk through security?
Yes. They are allowed in quantities above 3.4 ounces; tell the security officer and expect extra screening.
Do strollers and car seats count as luggage?
On major US airlines, one stroller and one car seat per child can be checked free and do not count toward your bag allowance.
Is it safe to fly with a baby on my lap?
It is allowed, but the FAA recommends that children fly in their own seat in an approved child safety seat.
