I can't imagine letting my daughter do this at the age of 12 (and as I work with middle schoolers, I can't imagine letting any of them do it, either).Flying is old hat to my DD, she's been flying cross country since the age of 6 months, and there's still just no way I would have put her on a plane at 12 years old and assumed she'd be fine and arrive at her destination. Heck last year she missed a connection at DTW and had to make arrangements for overnight accommodations, getting to hotel and back to airport, notifying those who were meeting her in IND and making alternate pick-up plans, etc. She was stressed by this at age 18, but took it in stride and worked it all out. However, there's no way she would have handled this when she was 12. If YOU are comfortable with it, that's your choice... but not mine.
FWIW, I made the statement "You only get one chance." It wasn't in defensiveness of how I choose to parent, and I wasn't insisting that mine is the only way to parent. I really don't care how YOU choose to do it. I just don't understand the choices people make when considering what's at stake, regardless of the miniscule chance of it happening to you. I was hoping someone could explain the rationale, but apparently not. It's fine, they are your kids, raise them how you want... just like I do.