We did that too in the mid-70s. What was more dangerous than usual about it?
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.