If you’ve ever noticed “SSSS” stamped on your boarding pass, you’ve been flagged for Secondary Security Screening Selection—an extra layer of airport security mainly implemented on flights entering or departing the United States. This doesn’t mean you’ve done anything wrong; rather, it’s usually part of a “random” selection process tied to an algorithm used by the TSA (Transportation Security Administration).

However, those four letters can mean a longer, more intense pre-boarding experience. Travelers with the “SSSS” code are typically pulled aside for a more thorough inspection, which might include:

• Being separated from your travel group

• A full pat-down by TSA agents

• Detailed inspection of all personal items (including electronics)

• Swabs for explosive residue

• Possible questioning about your travel plans

The code has drawn criticism and confusion, especially since frequent flyers and even federal employees have reported being flagged with no clear explanation. While frustrating, this extra screening is part of efforts to maintain air travel security—albeit one that can feel invasive and poorly explained.

If you see “SSSS” on your ticket, plan for extra time at the airport, and try to stay calm—it’s more bureaucracy than personal indictment.

Have you personally encountered this or a similar airport screening experience?