On a commercial passenger plane it's frowned upon.
On planes in general, many people jump nude for their 100th skydive - the original and best video of this has been scrubbed from youtube, but a quick search shows others.
Often screaming is included.
> the original and best video of this has been scrubbed from youtube
More US censorship. Nude skydiving, terrible. Indepth reviews of how to kill things with insane levels of weaponry? Featured video time.
On most commercial flights, it's not only frowned upon.
But if you want to f$ck around and find out, I'm sure it will make for a fun "How I Ended Up On the No Fly List" story.