I believe you've twisted the words of the OP here. I didn't read that the parent didn't believe the teen should fly alone, just that he/ she would like to see him get on the plane. You may not be familiar with age group characteristics, but teen years are a time of transition during which youth begin to learn adult skills which is why United allows 12 and up to travel unaccompanied. I still understand how a parent would fell better seeing their child actually board the plane. Maybe getting a gate pass will be a breeze and buying a ticket won't be necessary.