Air travel is designed to move millions of people quickly and efficiently, but for some passengers, the journey includes an unexpected delay marked by four letters on their boarding pass: SSSS. SSSS stands for Secondary Security Screening Selection, a designation used by the Transportation Security Administration (TSA) to indicate that a traveler has been selected for additional screening. Spotting this code—usually printed near the gate or seat number—means the airport experience will be more detailed and time-consuming than usual.
