Typically, minors under the age of 18 do not have to present identification for domestic U.S. travel. Airlines will accept identification from the responsible adult on behalf of the minor(s). For international travel, minors under the age of 18 must present the same travel documents as the adult.

For domestic flights within the U.S., children and infants under the age of 18 are not typically required by the TSA to provide identification. However, many airlines strictly require a birth certificate (original or copy) or a hospital birth record for lap infants under the age of 2 to verify their age and eligibility for free travel. This is because once a child turns 2, they are legally required to have their own purchased seat. For international travel, all infants must have a valid passport regardless of age. In 2026, while the TSA may not ask for an ID, it is highly recommended to carry a digital or physical copy of the birth certificate to avoid any boarding disputes at the gate, especially if your toddler is tall for their age and could be mistaken for a child over the age of two who requires a ticket.

Excellent question. The short answer is yes, for all practical purposes, a baby needs a birth certificate (or equivalent proof of age/identity) to fly within the United States.

Here’s a detailed breakdown of the rules, why they exist, and what you need to know.

The Official Rule (TSA and Airlines)

The Transportation Security Administration (TSA) does not require children under 18 to present identification for domestic flights. However, this is where the critical distinction comes in:

• TSA Security Checkpoint: They may not ask for ID for the child, but they will need to verify the child’s details to match the boarding pass. They often do this by asking a few questions of the accompanying adult.
• Airline Check-in (The Key Step): This is where the requirement comes in. Airlines are required by the Federal Aviation Administration (FAA) to verify the age of all passengers, including infants, for safety and ticketing purposes.

Why do airlines need proof of age? 1. To confirm the child is under 2 years old if they are flying as a “lap infant” (not occupying a seat). Lap infants fly at a reduced fare (often free for domestic flights, but taxes/fees may apply). The airline must ensure the passenger qualifies for this fare. 2. To prevent fraud (e.g., an older child traveling on an infant fare). 3. For safety and manifest accuracy.

Acceptable Documents for a Baby

Airlines will accept various documents to prove a baby’s age. The easiest and most universally accepted is:

• Official Birth Certificate: A certified copy issued by the state/county of birth.

Other acceptable forms of proof may include: Passport (even for domestic travel, this is excellent proof). Global Entry card (for the child).