How old must my son be in order to fly by himself

How old must my son be in order to fly by himself?
Okay, i know he can fly by himself. The real question is, how old musthe be in order to check himself out and back in for the flight home. He will be 16 when he is supposed to fly from virginia to arizona. Also, specifically which airlines are more minor flight friendly in this case. There wont be anyone to check him out, also what must happen in order for him to be checked out. Thanks in advance.
Air Travel - 4 Answers
Random Answers, Critics, Comments, Opinions :
1 :
He is able to if he is 16. I live in Virginia and my cousins who are 12 and 9 fly by themselves and check them selfs out. =)
2 :
you have to be 18, even if your like, 16 or 17, the air attendants still have to accompany your son out
3 :
You must be 18 to fly without being accompanied by airport staff. Otherwise (<17) your son will be classed as a UM (unaccompanied minor).
4 :
Well if he's 16 and you don't pay for unaccompanied minor service, the airline is going to treat him like any other passenger. There is no special treatment. No one is going to go with him and take him where he needs to go. If you want that you have to pay the extra fee.