Seeing “SSSS” printed on your boarding pass can be alarming, especially if it’s your first time flying. However, the four letters do not mean you are banned from flying or placed on a no-fly list. SSSS stands for Secondary Security Screening Selection, which means you have been selected for additional security screening before boarding.

There are several reasons why a traveler may receive the designation. Selection can be random, but it may also be associated with certain travel patterns, last-minute bookings, international itineraries, or a possible name match in security databases. Importantly, receiving SSSS does not automatically mean you have done anything wrong, and some travelers may receive it without ever learning the exact reason.

At the airport, the security process may take longer than usual. Officers can conduct a more thorough inspection of your carry-on luggage, perform a physical pat-down, or use explosive-trace testing on belongings and electronic devices. You may also be asked to turn on a phone, laptop, or tablet. The exact procedures can vary, but the purpose is to carry out additional screening before you are cleared to board.

If you see SSSS on your boarding pass, the best thing to do is arrive at the airport early and allow extra time for the screening process. Travelers who experience the designation repeatedly may also consider DHS TRIP, especially if they believe there could be a mistaken identity issue. For a first-time traveler, however, there is generally no reason to panic—SSSS is a security screening designation, not a declaration of guilt.