I agree with all the advice given so far but especially the part about knowing whether your teenager is mature enough to handle this. Some 16 year-olds can handle this sort of thing no sweat while others would get themselves into some kind of crisis situation 10 minutes after you wave goodbye. Talk to her parents to understand the extent to which she's taken smaller trips on her own (or with people her age) and how she handled herself. I took my first flight, ever, at about that age and I flew solo. And took shuttles/taxis on the far end. So I know from personal experience that it's totally reasonable for a responsible teen. OTOH, I had relatives who, at age 16, could barely get on the bus to school without getting lost, being late, forgetting their bag, etc. It depends so much on the individual teen.