Not STRICTLY on topic, but:
A fellow charter pilot friend told of a time when he had a charter to carry a load of young piglets in the back of a Navajo (in crates, not in the seats!). As is their wont, they were squealing their protest at being so confined from the moment they were boarded until approx FL60, whereupon it went quiet and they went to sleep. They stayed quiet all the way in the cruise at FL100, and started squealing at about FL50 on the way down again. I always wondered whether hypoxia was the cause..
Certainly a tip I was given when starting out on charter work was that if the pax had had a few bevvies before flying, a sure-fire way of getting them quiet was to cruise at FL100, where a combination of the alcohol and reduced oxygen would send most of them to sleep!
