Missy, you mention that the service is invaluable to you...I heartily agree, and this is why I use Virgin Atlantic. Fortunately, he flies from Miami, which has direct service with Virgin. It's the most kid-friendly airline I've ever come across.
Yes, Caitlinn, everything *will* be fine, but if we didn't worry, we wouldn't think about important things like reminding people to pack pens and stuff like that.
They shouldn't give your son a hard time, and yes, you'll be the first person they try to get ahold of if there is a problem. They wouldn't just leave him to fend for himself. That's one thing about kids and airports.
You might be amazed at just how many kids fly alone. My son usually ends up sitting with or near another kid alone on every flight...and he averages two flights per year for the past six years. Last time he flew there were two others and the time before that there were about four. Anyway, that's one flight, so you can imagine others, compounded on a daily basis, multiplied by years...yet you don't read about incidents of kids in an airport.