"John" wrote

I am not at all sure if this is accurate, but Ernie Gann in his book
"Fate is the Hunter" described an episode where he was carrying troops
in the back and they were getting a bit out of hand. He climbed and
the reduced oxygen resulted in a cabin of slumbering souls.

In airliners, all you have to do is change the cabin altitude pressure
setting, and you can do the same thing, and they do occasionally do this on
(especially on) oceanic red-eyes.

They don't have to go all that high to have a noticeable effect, but it does
make it easy for the flight attendants.
--
Jim in NC