Yes, a 9-year-old can fly alone, but they must use the airline's Unaccompanied Minor (UM) service. Most major airlines worldwide (such as Delta, United, British Airways, and Emirates) allow children between the ages of 5 and 11 to travel solo, provided a parent or guardian pays a mandatory UM fee, which in 2026 typically ranges from $100 to $150 per flight leg. This service ensures that the child is escorted by airline staff from the check-in desk, through security, to their seat on the plane, and is handed over personally to a pre-authorized adult at the destination. For a 9-year-old, the airline will generally restrict them to non-stop flights only or very specific "direct" connections to minimize the risk of being stranded during a delay. The parent must provide a notarized "Consent to Travel" form and the child must wear an identification lanyard throughout the journey. While some low-cost carriers (like Ryanair) do not allow anyone under 16 to fly alone at all, the major global carriers have robust protocols in place to ensure that a 9-year-old is safe, fed, and supervised throughout the entire travel process.