Yes, Delta Air Lines allows 15-year-olds to fly alone, and they are treated differently than younger children under their Unaccompanied Minor (UMNR) policy. For Delta in 2026, the UMNR service is mandatory for children aged 5 to 14. For teenagers aged 15 to 17, the service is optional. This means a 15-year-old can simply book a standard ticket and navigate the airport and connections independently without paying the $150 (each way) service fee. If they fly "independently," Delta agents will not provide an escort or monitor them during layovers. However, parents who feel their 15-year-old needs extra support can still "opt-in" and pay for the UMNR service, which provides a dedicated escort, access to the "Delta Sky Zone" lounges for kids, and a trackable wristband. If the 15-year-old is not enrolled in the program, they are subject to standard passenger rules, including the ability to fly on the last connecting flight of the day, which is prohibited for those in the mandatory UMNR age group.