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.