Travelers with a rare ‘SSSS’ on their plane tickets should prepare for a potentially bumpy situation before boarding their flight, experts have warned.

The frightening ‘SSSS,’ known formally as secondary security screen selection, can cause complications before going to a flight gate.

‘SSSS are indeed four dreaded letters that no traveler should want to see on,’ senior aviation writer Zach Griff said this month to Fox News Digital.

Griff explained ‘SSSS’ was ‘a measure implemented by security authorities in the US to screen certain passengers with additional checks.’

‘Selectees for this enhanced security are chosen in the days leading up to a flight when airlines share the manifest with US security authorities,’ Griff added.

Senior aviation writer Zach Griff explained why fliers would not want to see 'SSSS' on their boarding passes with Fox News Digital this month

Senior aviation writer Zach Griff explained why fliers would not want to see ‘SSSS’ on their boarding passes with Fox News Digital this month

The ‘SSSS’ printed on a traveler’s boarding pass means that fliers are required to go through extra screening by the Transportation Security Administration (TSA).

Some of these extra security measures include pat-downs, extra luggage inspection, and possible explosive residue swabs.

Fliers could find ‘SSSS’ on the boarding tickets for no reason, and the Department of Homeland Security website explained they ‘cannot be disclosed’ for security purposes.

Certain things like random selection, booking one-way tickets, purchasing boarding passes using cash, or traveling to a red-flag destination could be red flags, according to The Points Guy

Griff explained that ‘SSSS’ on tickets have also caused most fliers to ‘not be able to check in online’ and would also ‘receive a printed ticket from an agent.’

Various travelers have gone through this experience, including Jordyn Verzera and JT Mocarsk.

The 'SSSS' printed on a boarding pass means that flier will be required to go through extra screening by the Transportation Security Administration

The ‘SSSS’ printed on a boarding pass means that flier will be required to go through extra screening by the Transportation Security Administration

Verzera, who’s known as the ‘face behind The Mobile Homie‘ travel blog, recalled a rocky airport incident after seeing ‘SSSS’ on her boarding pass.

The travel expert explained her recent experience with the additional screening process with Fox News Digital this month. 

Versera revealed she was not able to get her boarding pass on an airline app and needed to speak with a gate agent.

‘They had to give me a printed boarding pass,’ Verzera told Fox News Digital.

‘He [Mocarski] could still use his digital one, and then I had to carry this pass around.’

The blogger added the ‘SSSS’ on her ticket was ‘marked and circled’ and needed to show her boarding pass ‘every step of the way.’

‘Instead of just going through one form of security… you had to get to the gate early, and they did an extra-deep screening when you departed,’ Verzera said. 

‘But where the big thing was, is, once we arrived, we actually ended up having to go through customs… and that was when the really deep search began.’

(Stock image only) Travel blogger Jordyn Verzera was not allowed to check in for her flight on an airline app because 'SSSS' was on her ticket

(Stock image only) Travel blogger Jordyn Verzera was not allowed to check in for her flight on an airline app because ‘SSSS’ was on her ticket

Verzera was forced to remove everything from her luggage, including toiletry items. 

Airport officials also requested she turn on her laptop and place all her unpacked items onto a conveyor belt to be swabbed.

She arrived at the airport early to receive her boarding pass after spotting an ‘SSSS’ again, but was forced to wait three hours in line for the ticket.

Once Verzera got her ticket, she waited another hour to go through security screenings at customs.

Mocarski got lucky after finding an ‘SSSS’ on his boarding pass in Rome, Italy, and revealed his experience was faster than Verzera’s.

Mocarski claimed the ‘SSSS’ matter depends on the country or where the traveler is going and what the search entails, while speaking with Fox News Digital.

Griff agreed with the travel enthusiast, and that some airports may require ‘more screening’ and a ‘personalized interview.’

Mocarski eventually understood why TSA were implementing ‘SSSS’ on random boarding passes and that staying calm and respecting agents would help.

He and Verzera also suggested fliers purchase traveler insurance when selecting their flights.

Verzera arrived early at an airport after discovering 'SSSS' on another ticket and waited three hours to receive her boarding pass

Verzera arrived early at an airport after discovering ‘SSSS’ on another ticket and waited three hours to receive her boarding pass

A TSA spokesperson explained the ‘SSSS’ on boarding tickets are meant to help the ‘transportation security mission’ in an email to Fox Digital News.

‘Security measures begin long before passengers arrive at the airport,’ the TSA spokesperson wrote. 

They continued the explanation by writing the additional security measures are in place ‘from the time passengers get to the airport until they arrive at their destination.’ 

The spokesperson also confirmed passengers are ‘randomly selected for enhanced screening.’

The dreaded ‘SSSS’ on boarding passes are unavoidable, meaning fliers who spot the unfortunate letter will have no choice but to undergo the extra security measures.