What do you call a very polite airplane?

This joke soars on the wings of clever wordplay, specifically a pun that plays on the sound of words. The humor comes from taking the common term for an aircraft, "plane," and twisting it to sound like "plain" in the phrase "plain old gentleman." It's a delightful linguistic trick that relies on the listener expecting one meaning and then being surprised by another, creating an unexpected and amusing image.

The idea of a "gentleman" has a long history, traditionally referring to a man of good breeding and courteous manners. When we combine this rather old-fashioned concept of politeness with a modern marvel like an airplane, the contrast (Review) itself is a bit silly. The punchline cleverly uses the idiom "plain old gentleman" to describe someone unremarkable but respectable, while simultaneously making a nod to the polite airplane.

It’s this simple yet effective double meaning that makes the joke take off. The unexpected connection between a respectful demeanor and a mode of transport, all hinged on a single word, delivers a lighthearted chuckle without requiring too much thought. It’s a testament to how language can be bent and shaped for a good laugh.