Every year, millions of Americans shuffle through airport security lines, half-listening to overhead announcements while digging laptops out of bags and removing shoes. Most of those announcements blend into background noise. But some of the words and codes flying around an airport carry serious weight. From security alerts to boarding pass markings, there’s a whole secret language happening right under your nose—and knowing what it means could save you time, stress, or at least satisfy your curiosity.
Code Bravo is the one that should grab your attention
If you’re walking through an airport and suddenly hear someone shout “Code Bravo,” pay attention. This is the code that security personnel use to flag a general security threat in the terminal. It could mean anything from an unattended bag to a suspicious individual. The phrase is deliberately loud and alarming. Security workers sometimes shout it specifically to startle people in the area. Why? Because the person who flinches or reacts unusually might be connected to whatever triggered the alert in the first place.
According to reports, Code Bravo is the code word you absolutely never want to hear at an airport. It signals that something is wrong, and it usually means security is actively trying to locate a problem. If you hear it, stay calm and follow instructions from airport staff. Don’t run. Don’t panic. Just be aware that security is handling a situation, and getting out of the way is the best thing you can do. Cooperation speeds everything up for everyone.
SSSS on your boarding pass means extra screening
Ever glance at your boarding pass and notice the letters “SSSS” printed on it? That stands for “Secondary Security Screening Selection.” It means the Transportation Security Administration—better known as TSA—has flagged you for a more thorough security check. This can happen for a variety of reasons. Maybe you bought a one-way ticket. Maybe you paid with cash. Or maybe your travel pattern just matched a profile in the system. It doesn’t necessarily mean you did anything wrong.
What it does mean is that you should plan for extra time at security. The enhanced screening can include a full pat-down, swabbing of your belongings for trace chemicals, and a closer look through your carry-on bags. It takes longer than the standard process, so arriving early is critical. If you spot those four letters on your boarding pass, don’t stress—but definitely don’t dawdle getting to the airport. Give yourself at least an extra 30 minutes beyond your usual arrival time.
Code Adam means a child is missing
Most people have heard “Code Adam” in retail stores like Walmart, where the term originated. But airports use it too. It signals that a child has gone missing somewhere in the terminal. When this code goes out, staff members immediately begin watching exits and scanning the area for the child matching the description. Airports are massive, crowded places. Kids can wander off in seconds, especially near shops or play areas. The code triggers a coordinated response that locks down attention on every door and hallway.
If you’re traveling with children, this is a good reminder to keep them close, especially in busy terminals. Some parents use matching bright-colored shirts or attach a small tracker tile to their child’s backpack. It’s also smart to teach kids what to do if they get separated—like finding a uniformed worker or staying in one spot. Hearing Code Adam at an airport is unsettling, but it means everyone is working together to bring that kid back to their family quickly.
Airline delay codes tell the real reason flights are late
Ever been stuck at a gate with no explanation for why your flight is delayed? Airlines and airports use codes from the International Air Transport Association to categorize delays. “FS” means there’s a shortage of flight crew. “DG” means the aircraft has been damaged while on the ground. And “PO” means your flight is overbooked. These codes are used internally, so you’ll rarely hear them announced. But sometimes you’ll catch them on status boards or overhear gate agents using them.
Knowing these codes can actually help you make smarter decisions. If the delay is crew-related (FS), it might resolve quickly once a replacement shows up. But if the plane is damaged (DG), you could be looking at a much longer wait or even a gate change. And if the flight is overbooked (PO), that’s when airlines start offering travel vouchers to volunteers willing to take a later flight. Have you ever wondered why some passengers jump at those offers? Now you know—the delay code tells the whole story.
Angel and Code 300 are the ones nobody wants to use
Once you’re on the plane, the code words keep coming—and some are far more serious. “Angel” and “Code 300” are used by flight attendants to indicate that a passenger has died during the flight. It’s a grim reality that happens more often than most people realize on long-haul flights. The codes allow crew members to communicate the situation discreetly without alarming the rest of the cabin. They need to coordinate how to handle the situation calmly and respectfully.
In most cases, the crew will try to move the deceased person to a less visible area of the plane, sometimes to an empty row or a crew rest area if one is available. The flight may also divert to the nearest airport depending on the circumstances. These codes exist so that the situation can be managed with dignity. If you ever hear “Angel” whispered between crew members, it’s best to simply stay in your seat and let the staff do their job without interference.
Squawk 7500 signals a serious threat to the aircraft
Pilots have their own set of codes, and “Squawk 7500″—sometimes called “Hotel 7500″—is one of the most alarming. This code tells air traffic control that the plane is under threat, which could mean a hijacking or another serious security situation. The word “squawk” refers to a transponder code that the pilot enters into the aircraft’s system. It silently communicates the emergency to controllers on the ground without making any announcement that passengers or potential threats would hear.
This is one of those codes that passengers will almost never know about in real time. It’s designed that way on purpose. The entire point is to get help from the ground without escalating the situation inside the cabin. Air traffic controllers who receive a Squawk 7500 signal will immediately begin emergency protocols, including alerting military aircraft if necessary. The system works because of its secrecy. It’s a stark reminder that a lot of safety work happens behind the scenes every time a plane takes off.
Mermaid is the code for an oversized seat situation
Not every code word is doom and gloom. “Mermaid” is reportedly used by cabin crew to indicate that a passenger is taking up more than one seat. It’s a tactful way for flight attendants to communicate the situation without embarrassing anyone. Airline seats keep getting narrower—especially in economy class—so this situation comes up more than you’d think. The code allows crew to discuss logistics, like whether to reseat nearby passengers, without drawing attention to anyone.
This is one of those things that reminds you how much communication happens between flight attendants that passengers never pick up on. The use of a code like “Mermaid” is really about maintaining courtesy and professionalism. It’s also a practical tool—if a passenger needs an extra seat, the crew may need to adjust seating arrangements quickly before takeoff. So while the word itself sounds whimsical, it serves a very real operational purpose that helps keep the cabin organized and comfortable for everyone on board.
Code Yellow and Pan Pan signal medical problems onboard
Medical situations happen in the air all the time. “Code Yellow” is the term used for a minor, non-urgent medical issue on a flight. Maybe someone feels faint or has a mild allergic reaction. It alerts the crew that some attention is needed, but the situation isn’t critical. It helps staff prioritize without dropping everything. In many cases, a Code Yellow can be handled with basic first aid supplies that every commercial aircraft carries in its onboard medical kit.
“Pan Pan” is a step up in urgency. This phrase signals a more serious problem—whether medical or mechanical—that isn’t immediately life-threatening but requires swift action. Pilots might declare a Pan Pan to get priority landing clearance. Flight attendants might use it to request a doctor among the passengers. It’s less severe than a “Mayday” call, which indicates imminent danger, but it still gets everyone’s full attention. Knowing the difference between Code Yellow and Pan Pan helps put any overhead chatter into perspective if you happen to overhear it.
What chimes and dings on the plane actually mean
Beyond spoken codes, those chimes you hear during a flight carry their own messages. A single ding usually means a passenger has pressed the call button. Two chimes in a row often signal communication between the cockpit and the cabin crew. And a series of rapid chimes during critical phases like takeoff and landing can indicate that the crew needs to prepare for something important. Every airline has its own system, so the sounds can vary between carriers like Delta, United, or American Airlines.
Most of the time, those chimes are completely routine. A ding right after the seatbelt sign turns off simply tells the crew they can start cabin service. But if you hear an unusual pattern—say, three or four rapid chimes in a row—that could signal something that requires immediate crew attention. There’s no need to panic over every sound, though. The vast majority of chimes are just part of the normal flow of a flight. Think of them as the plane’s version of text messages between the crew.
Airports and airplanes run on a hidden language that most travelers never notice. From Code Bravo in the terminal to Squawk 7500 in the cockpit, these codes exist to keep operations smooth and passengers safe. Knowing a few of them won’t change how you fly, but it does pull back the curtain on what’s really happening around you. Next time you’re at the gate or cruising at 35,000 feet, listen a little closer—you might just catch something interesting.
