Travelers passing through airports and boarding aircraft routinely hear announcements and short phrases intended for staff, not passengers. One of those phrases, "Code Bravo," has been highlighted in recent reporting as a code associated with a general security issue that staff may shout to draw attention and help locate a problem.
Other codes appear in public and private communications for a range of nonroutine situations, from missing children to medical events and security threats. Reporting by the Daily Mail on Sept. 10, 2025, summarizes several such terms and notes that some codes are used specifically by airlines, airports or regulatory bodies to manage incidents while minimizing alarm among travelers.
On the ground, a variety of three-letter and short codes are used to indicate delays or operational problems. The International Air Transport Association maintains delay codes that are commonly adopted across the industry; examples cited in recent coverage include "FS" for a shortage of flight crew, "DG" for a damaged aircraft while on the ground, and "PO" to indicate an overbooked flight.
Codes also appear on travel documents. The boarding-pass marker "SSSS," which stands for Secondary Security Screening Selection, signals that a passenger has been chosen for additional screening by the Transportation Security Administration in the United States. Travelers who see that notation should expect an enhanced security check that can take longer than standard screening and may cause delays.
A distinct set of terms is used inside aircraft and among cabin crew to handle incidents without alarming passengers. Reports cite "Code Adam" as a phrase for a missing child. "Code Yellow" is used for minor, less urgent medical issues, while "Pan Pan"—a standard maritime and aviation urgency call—signals a serious problem that is not immediately life-threatening. By contrast, the transponder squawk code "7500" (sometimes referred to on the radio as "Squawk 7500" or "Hotel 7500") is used by pilots to indicate the aircraft is under unlawful interference, allowing them to alert air traffic control without alarming those on board.
Some staff codes denote particularly sensitive or rare occurrences. Accounts referenced in coverage say that terms such as "Angel" or "Code 300" may be used to discreetly indicate that a passenger has died during a flight, enabling cabin crew to coordinate a response and manage the situation. Other colloquial terms reported among crews include "Mermaid," used to describe a passenger occupying more than one seat.
Airlines, airports and security agencies do not always use the same terminology, and local practices can vary. Industry shorthand and radio brevity codes serve operational needs: they enable staff to communicate efficiently, provide appropriate responses and, in many cases, avoid causing undue concern among passengers.
Passengers who overhear code words should generally follow instructions from airline and airport staff. For issues such as enhanced screening indicated by "SSSS," travelers can expect longer processing times and are advised to allow additional time when possible. For security or safety incidents, staff will typically issue public instructions only when necessary.
The use of coded language in aviation reflects efforts to balance clear internal communication with passenger management. While some of the phrases described in recent media reports are widely known, others are informal or vary by carrier and region. Travelers with concerns about a specific situation or a notation on travel documents are advised to seek information directly from airline or security personnel.