Originally Posted by
CDTraveler
Also, kid when dressed up can pass for 18.
As long as he can convince TSA he's under 18, and UA that he's 15 (assuming he'll still be 15 at time of the trip, but he should bring a passport to prove his age at the ticketing counter just in case).
http://www.united.com/web/en-US/cont...s/default.aspx
And for the record, kids aged 12-17 can travel without accompaniment on UA:
Children ages 12 to 17 can use United's unaccompanied minor service for travel on nonstop flights operated by United or United Express, or they can travel as adults on any flights without using United's unaccompanied minor service.