Hard to tell as PJ-Comix pointed out that CNN plays in public places.
Although I have been in airports in which FNC was playing. In fact, now that I think of it, FNC was on (only one occasion that I can recall) in Boston's Logan airport.
Travelling the hockey/ ice rink/ motel circuit this year, I've noticed considerably more 'public' tv's tuned to FoxNews over CNN from last season to this.