What's a plane's favorite flavor?

This little groaner flies high on a classic case of wordplay. The humor lands because the word "plane" is a homophone, meaning it sounds exactly like "plain." It's a pun in its purest form, swapping one word for a sound-alike to create a silly, unexpected image. This type of joke is the bread and butter of dad humor, relying on a simple linguistic trick that's so straightforward it's charmingly groan-worthy.

The choice of "plain vanilla" adds another subtle layer. The phrase is a common idiom for anything that is basic, standard, or without any fancy extras. In a way, it’s a fitting personality for an airplane, a machine focused on the straightforward function of getting from point A to point B. While first-class might be fancy, for most people, the experience of air travel is pretty standard. The joke cleverly combines a simple pun with a concept that humorously fits the subject.