GCN tours
I have flown the GCN tours over the Canyon a few times, and always took the same company. AirStar Helicopters [mostly red livery, some are white] are located at GCN airport.
The flight is very smooth, and the pilots are great.
About the "No flights into the canyon": there is a rule now that says that no aircraft may go below south rim altitude. It really sucks, and I got the pilot to get down a little off of the original route [not with aistar tho].
So if you get a flight from north las vegas to GCN, walk over to airstar [it's a little off the airfield]. It's real fun.
BTW: I'm not flying for Airstar *laughs*