So kids 12 and older can just travel by themselves?
I'm thinking of sending a 15-year-old on a flight by himself. He's a seasoned traveler, would fly nonstop, and will have family to pick him up at the airport. And in this age of cell phones, I'm not worried about communicating with him if something went wrong.
That said, I checked the rules just to make sure it was "legal." Not only is it legal, but I was surprised to see that the USA airlines seem to allow children aged 12 and older to travel unaccompanied without restrictions. Twelve seems rather young to me -- especially on connecting flights when the probability of something going materially wrong is higher (especially on the last connection of the day).
I honestly can't recall seeing young teens travelling by themselves. Is it a common practice? Given how high the "unaccompanied minor" fees are, I would think lots of kids get sent off to visit friends/family with their parents just "hoping for the best."