Quite a few of those planes (and some helicopters) crashed into the canyon. I'm no engineer but has something to do with a downdraft. Anyhow, a couple of years after I took the plane ride, one of them crashed. The companies would start these excursions, then quit when there was a crash, then start up again, then quit after another crash, etc. etc. I sure hope they don't do these flights anymore.
I didn't realize that. I just remember it being a really thrilling ride. The pilot came in real low so you couldn't see the canyon ahead and then Pow! the bottom just dropped out from under you as you went over the edge and he dropped down inside. I was probably 13 or 14 years old.