Originally Posted by
Firebug4
Both Border Patrol and CBP can and do airport operations just has they do train and bus terminal operations. If your friend is in the country illegally. He takes his chances that he may run into law enforcement just like any other person that is involved in illegal activity.
I think the point was to minimize such an encounter.
Originally Posted by
copwriter
Unless your friend's name appears on a no-fly or other alert list, it's highly unlikely he will have any difficulty. The TSA looks for legit government-issued identification. If the State of Idaho issued the license, it will have all the appropriate markings the ID checker is looking for. If you're not crossing any international borders, there's no reason for anyone to be checking citizenship (unless you're passing through Arizona, which is a whole different story).
Even in AZ, someone holding a valid DL and "looks American" is ulikely to have a problem there, IMO.