Ever notice the four-letter code 'SSSS' on your boarding pass?

Apparently, it's the last thing you want to come across as it can cause major delays when travelling to the United States. It means that you're going to be subjected to additional security checks at the airport. The news everyone wants to hear while waiting to board a flight, NOT. The code stands for Secondary Security Screening Selection and as mentioned above, you don't want to be in that category. A spokesperson for the Transportation Security Administration explained what the code involves.

I’m SSSS on EVERY flight. Special treatment includes @TSA feeling & squeezing you & every single item in the luggage pic.twitter.com/O2K5KPx0Zt

— Bahman Kalbasi (@BahmanKalbasi) August 5, 2017

In conversation with Business Insider, a statement from the spokesperson said:

"SSSS stands for Secondary Security Screening Selection and it appears on a passenger’s boarding pass when they’ve been selected by TSA’s Secure Flight system for enhanced security screening".

The code can be handed out at random but it's thought that it's more common in situations where flights are one-way, paid for with cash and are returning/going to a high-risk destination. Apparently, the SSSS code is part of a system named Secure Flight and it chooses how people are selected for extra security checks with the statement explaining:

"Secure Flight is a risk-based passenger pre-screening program that enhances security by identifying low and high-risk passengers before they arrive at the airport by matching their names against trusted traveller lists and watchlists".

The dreaded SSSS boarding pass. I can assure you they don't stand for Super Special Service Selection. pic.twitter.com/hWPiTnw1SS

— Rob Begg (@rbegg) March 2, 2014

This story first circulated last year but it's being talked about again recently and we figure that it's something people heading stateside should be told in advance in case it's something you ever come up against.