What Is the Significance of “SSSS” on Airline Tickets?

Those four letters stand for Secondary Security Screening Selection, and they can turn a routine trip into an anxious wait under fluorescent lights. When SSSS appears on your boarding pass, it means you’ve been flagged for intensive screening: more questions, more scans, more swabs, and often a full search of your belongings. You’ll usually be pulled aside at the security checkpoint or at the gate, and you may board last.

This isn’t random chaos. It’s part of the TSA’s Secure Flight program, which quietly analyzes passenger data before you even reach the airport. Your name, date of birth, travel patterns, and sometimes one-way or last-minute tickets can all play a role. Being selected doesn’t automatically mean you’ve done anything wrong—but it does mean less privacy and more scrutiny. Knowing what SSSS means won’t stop it, but it can keep you from panicking when those letters appear.