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 U.S. domestic flights in 2026, the rules for children are fairly standardized across major carriers like Delta, United, and American. Children under age 2 can fly for free as a "lap child," though you must still notify the airline to have them added to your ticket. Once a child turns 2, they must have their own purchased seat. Most airlines do not require a formal ID (like a birth certificate) for children under 18 on domestic flights, but it is wise to carry a digital copy of their birth certificate just in case their age is questioned for a lap-child fare. For Unaccompanied Minors (usually ages 5–14), most airlines charge a mandatory service fee (approx. $150 each way) and require specific paperwork and a dedicated gate-pass for the adult dropping them off. In 2026, the "Family Seating" rules have improved, with many airlines now guaranteeing that a child under 13 will be seated next to an accompanying adult at no extra cost, even on basic economy fares, provided the flight isn't already fully booked.