Folks in Dallas-Fort Worth airport got an eyeful when this butt-naked dude casually strolled through one of the concourses, past a TGI Fridays -- hey, for some folks it's always Friday!!!

Mind you, there was surprisingly little fanfare or shock from his fellow travelers, besides the guy who recorded this Monday night. He couldn't help yelling the obvious, "There's a naked guy in the airport!"

That brilliant color commentary was very much appreciated by the nudist himself, who turned, smiled and pointed at the camera as if he were an all-star athlete walking off the field.

Cops weren't as impressed and took the man into custody for a mental health evaluation ... and he was not booked for any crime.