I would assume that people have always found farting amusing.
Is there such a thing as timeless comedy? Page 3
Unless they were in a submarine or a space shuttle then yes.
I think that comedy itself is timeless. Comedy performances and writing of course can become dated because of the content as fashions change. I'm not a particular fan of the Pythons but...a parrot can die at any time...
I think sometimes it depends on if you remember the original show or what was happening around the time it was made.
About 10 years ago in Australia there was a mock news/current affairs program done. Some of "news" stories were completely made up but others were based on things that were happening around that time. The show has been replayed recently and even though the I didn't see it when it originally aired I still find the stories based on real events funny because I can remember them happening. However I think if I was only 14/15 and couldn't remember the events I wouldn't find it funny.