The flight attendant served peanuts at 30,000 feet.

This joke tickles our funny bone with a clever bit of wordplay, a classic humor mechanism. The punchline hinges on the double meaning of "high-altitude snacks." On the surface, it literally refers to snacks served at a high altitude, like 30,000 feet in an airplane. But the humor comes from the subtle, implied second meaning: "high" as in feeling intoxicated, and "snacks" as in the munchies often associated with that state. The setup creates a mundane scenario of airplane service, only for the punchline to introduce this unexpected, slightly subversive twist.

In the real world, airplane snacks have a long and sometimes contentious history. For decades, airlines offered full meals, even in economy, but cost-cutting measures have largely reduced offerings to small, pre-packaged items like the ubiquitous peanuts, pretzels, or cookies, especially on domestic flights. This common experience of limited inflight refreshments sets the stage for the joke's playful subversion. We all expect the standard fare, which makes the idea of "high-altitude snacks" taking on a different, more recreational meaning so amusing.

The joke expertly plays on our shared cultural understanding of both air travel and certain colloquialisms. By juxtaposing the sterile, regulated environment of an airplane cabin with the informal, implied reference to "getting high" and the snacks that might accompany it, the joke creates a lighthearted moment of unexpected humor. It's a quick, witty jab that relies on the audience making the connection between the literal and the implied, proving that sometimes the best humor is found in a simple turn of phrase.