What do you call a boat that can fly?

In the nautical context, a “boat” is a watercraft designed for travel on water. When the question asks what you would call a boat that can “fly,” the listener might expect an answer that combines elements of aviation and boating, like “airboat” or “flying boat.”

The term “float” has multiple meanings. In the context of water, to “float” means to stay on the surface of the water without sinking. In aviation, “floats” are pontoons attached to the bottom of an aircraft to allow it to land on water. Additionally, “float” can also refer to the action of flying or hovering in the air, as in “floating on air.”

The joke plays on these different meanings. The word “float” is both relevant to boats (which float on water) and to the concept of flying (as in floating through the air). The humor arises from the unexpected yet oddly fitting answer. Instead of giving a term that explicitly combines boating and flying, the joke offers “float,” which subtly and amusingly ties the two concepts together.