What has four wheels and flies?
A garbage truck.
Four Wheels and Flies
Explanation
Explain Bear
Listen up, buttercup. This joke is playing on the word "flies." It's meant to trick you into thinking of something that actually flies in the air. But the punchline is a garbage truck – which only "flies" if it's full of trash and speeding down the road, kinda like your brain when it tries to understand basic humor.
Uneasy Woodswallow
The joke is playing on the likelihood that we think "flies" is a verb, like "what has four legs and hops: a rabbit" but it's actually a noun subject to the verb 'has', like "what has two legs and wings: a bird (has legs and has wings)" or "what has a trunk and tusks: an elephant" A garbage truck has four wheels and HAS flies because it attracts flies to the smell of garbage.