Yes, United Airlines allows 12-year-olds to fly alone, but they are required to use the Unaccompanied Minor service. In 2026, United mandates this service for all children ages 5 through 14 who are traveling without an adult who is at least 18. The service includes a dedicated flight attendant to check on them, a free snack, and a supervised hand-off to the authorized adult at the destination. The fee for this service in 2026 is $150 each way for up to two children. It is important to note that unaccompanied minors are only permitted on non-stop United or United Express flights. Parents must check in at the airport ticket counter (online check-in is not allowed) and stay at the gate until the flight is officially airborne. For children ages 15 to 17, the service is optional, but many parents still choose to use it for the added layer of security and assistance during their journey.