There are words being spoken over your head on every flight that you were never meant to understand. One of them might already describe you.
Commercial air travel runs on two parallel systems of communication. The official one involves FAA-mandated acronyms, standardized aviation abbreviations, and the NATO Phonetic Alphabet, which pilots use when talking to each other and to Air Traffic Control.
Instead of reading out individual letters, a pilot will say something like “Delta Alpha November 2-3-4-5 Tango at Gate Bravo 12” rather than spelling out “D A N 2345 T.”
The system exists to eliminate misunderstandings over radio frequencies where clarity can be a matter of life and death.
Then there is the unofficial one.
According to a report by Wander, a luxury vacation rental company, flight attendants and crew members have developed their own informal vocabulary for what happens in the cabin.
Some of it is practical. Some of it is pointed. And some of it, passengers would probably prefer not to know about.
What “Mermaid” Actually Means
The term getting the most attention right now is “mermaid,” and it has nothing to do with folklore.
Kolin Jones, a pilot and the founder and CEO of private aviation company Amalfi Jets, explains that the word is used among flight crew to describe passengers who spread themselves out across multiple seats, taking up more space than their ticket entitles them to.
Think sprawling across an empty row on a quieter flight to claim the whole thing, or encroaching into the seat beside them.
Forbes has described it as a passive-aggressive nickname for passengers who block other travelers from sitting nearby, noting it comes up most often on flights where empty seats are abundant and easier to colonize.
Jones is clear that hearing the word is not a cause for alarm. It is not an emergency code and carries no operational consequences. That said, it might be worth glancing at your armrests.
The Medical Codes Worth Knowing
Beyond the colorful passenger nicknames, flight crew also use coded language for situations that do carry real urgency.
“Angel” and “Code 300” are terms used by certain airlines and aviation companies to signal a medical emergency onboard.
Jason Martinelli, director of operations at Cirrus Aviation Services, has described these as indicators that a passenger is incapacitated, unresponsive, or in serious distress. The coded phrasing allows crew to communicate quickly and discreetly without causing alarm in the cabin.
“Code Yellow” and “pan-pan” are two additional terms flagged by Wander as indicators of a medical incident during a flight.
Pan-pan, for those unfamiliar, is actually a formal international distress signal used in maritime and aviation contexts to indicate an urgent situation that has not yet reached the level of a full emergency.
Why the Coded Language Exists
The dual language system aboard commercial flights is not accidental.
Official terminology keeps pilots and controllers in sync across international airspace. Unofficial terminology gives crew a way to manage the social dynamics of a pressurized tube carrying hundreds of strangers, without broadcasting every observation over the intercom.
Most passengers will never know what is being said. But now, at least, if the word “mermaid” drifts past from the galley, there is no mystery about what it means or who it might describe.