The commentary on the DVD includes a bit of info on this scene- when Graves asks
“Have you ever seen a grown man naked?”,
the question that was the original idea for the script was much more graphic, and definitely would have given the film an R rating.
The Otto Pilot scene alone might warrant an R in today’s society, not to mention Bridges’s drug use. I would rank Airplane in my top 10 comedies, but IMO, nothing tops Monty Python And The Holy Grail.