No, a child does not need a passport for a domestic flight within the United States. The TSA does not require travelers under 18 to show any identification at airport security checkpoints on domestic routes, so a passport, REAL ID, or birth certificate is not legally required to get your child through the line. The adult flying with the child still needs valid ID, and a few specific situations make it worth tucking a copy of the birth certificate into your bag anyway.
What TSA Requires for Children
The rule is short. Children under 18 do not need to show identification to pass through security on a domestic flight.1Transportation Security Administration. Acceptable Identification at the TSA Checkpoint The accompanying adult presents their own ID, and the child walks through with them. No form, no birth certificate at the podium, no age at which a minor suddenly needs a driver’s license.
There is one narrow exception. If a child is flying alone and has TSA PreCheck through a Known Traveler Number, they need an acceptable ID to receive expedited screening.2Transportation Security Administration. Do Minors Need Identification to Fly Within the US For every other child on a domestic flight, TSA has no ID requirement.
REAL ID enforcement, which began May 7, 2025, applies to travelers 18 and older.3Transportation Security Administration. TSA Begins REAL ID Full Enforcement Your child is not affected by it. Sort out your own ID before you worry about theirs.
When to Bring Documents Anyway
TSA won’t ask for your child’s ID, but airlines sometimes will. Carriers set their own policies for verifying a child’s age or identity, and TSA recommends checking with your airline about any airline-specific requirements for travelers under 18.1Transportation Security Administration. Acceptable Identification at the TSA Checkpoint A copy of the child’s birth certificate covers nearly every situation that comes up. It proves both identity and age, and it costs nothing to bring.
Two situations bring the request most often.
Lap Infants
Federal aviation regulations let a child who has not yet turned two sit in an adult’s lap instead of a purchased seat.4Federal Aviation Administration. Use of Child/Infant Restraint Systems in Aircraft Airlines don’t charge for a lap seat, so they have a direct reason to verify the child qualifies. Expect the gate or check-in agent to ask for proof of age, and bring the birth certificate (or a photocopy). A passport works too, but there’s no reason to get one just for this.
If your child turns two mid-trip, most airlines require a purchased seat for the return. Book accordingly and bring the birth certificate so no one at the gate has to guess which side of the birthday you’re on. Airlines also set their own minimums for how many days old a newborn must be before flying.
Unaccompanied Minors
When a child flies alone, the airline’s policies matter far more than TSA’s. Airlines typically require documentation for both the child and the adults handling drop-off and pickup, and the specific rules differ by carrier.5USAGov. International Travel Documents for Children Call the airline well before the travel date to find out the age restrictions, the forms you’ll need to complete, and the ID the adults on each end must bring. Unaccompanied minor service also carries a fee, and a couple of carriers don’t offer it at all.
TSA PreCheck With Kids
If you have PreCheck, whether your children can join you in the lane depends on their age.
- Children 12 and under can come through the PreCheck lane with you regardless of what their boarding pass says. The indicator does not need to appear on the child’s pass.
- Teenagers 13 to 17 can use the PreCheck lane only when the indicator appears on their own boarding pass. That happens when the teen is booked on the same reservation as the adult with PreCheck, and the adult’s boarding pass also shows the indicator.6Transportation Security Administration. TSA PreCheck for Families
Families get caught by this when they book a teenager’s ticket separately, maybe with points or a different card, and then find out at the airport that the teen can’t come through the fast lane. Book everyone on one reservation.
Traveling Without Both Parents
No federal law requires a consent letter for a domestic flight when a child travels with one parent, a grandparent, or a family friend. Carrying one can still prevent an awkward conversation at the gate, especially when the adult and child have different last names, when parents are separated, or when the accompanying adult is not a parent at all.
A useful letter includes the child’s full name and date of birth, the traveling adult’s name and relationship to the child, the non-traveling parent’s name and contact information, and the travel dates and destinations. The U.S. Department of State recommends notarized consent letters for any minor traveling without both parents.7U.S. Department of State. Travel With Minors Notary fees for a single signature usually run between $2 and $15. Bring a copy of the child’s birth certificate along with it.
Flights to U.S. Territories
Flights from the mainland to Puerto Rico, the U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands are domestic. U.S. citizens do not need a passport, and the same TSA rules apply: adults need valid ID, children under 18 do not.1Transportation Security Administration. Acceptable Identification at the TSA Checkpoint These destinations feel international but legally aren’t.
The moment a trip crosses into a foreign country, that changes. Every traveler needs a passport, children included, at any age. If your itinerary includes a cruise from a U.S. territory that stops at a foreign port, or a connection through a non-U.S. airport, passport rules apply to everyone in the group.