In 2026, whether a 13-year-old can travel abroad alone depends strictly on the airline's "Unaccompanied Minor" (UM) policy. Many major airlines, such as British Airways and Virgin Atlantic, have recently updated their rules to require passengers to be at least 14 or 16 years old to travel completely alone. For a 13-year-old, most "Full-Service" carriers will require you to pay for the "High-Fidelity" UM Service, where a staff member escorts the child through security, stays with them during layovers, and hands them off to a designated adult at the destination. However, many "Budget" airlines (like Ryanair or easyJet) do not offer this service and strictly prohibit anyone under 16 from traveling without an adult. It is a high-fidelity requirement to check the "Minor Travel Consent" laws for both the departure and arrival countries; you will likely need a notarized "High-Fidelity" Letter of Consent from both parents. Without this documentation and a confirmed UM booking, the child will be denied boarding at the high-fidelity check-in counter.