What Is a Known Traveler Number, and What Do You Do With One?

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A Known Traveler Number (KTN), also called a Trusted Traveler Number, is a number issued by the US Transportation Security Administration (TSA), Department of Homeland Security (DHS) or Department of Defense (DoD) that indicates that a person has undergone some type of pre-flight background check or other screening before checking in for a flight. Adding your Known Traveler Number to an airline reservation greatly increases your chances of being able to use the TSA's PreCheck® security screening lanes at participating US airports and permits you, if you are a Global Entry member, to take advantage of expedited customs processing.

How Can I Get a Known Traveler Number?

The easiest way to get a KTN is to enroll in either the PreCheck® or Global Entry program. If your application is approved, you will receive a KTN. Your Global Entry KTN is linked to your passport information, while a PreCheck® KTN is linked only to the personal information you supplied when you enrolled. Participating airlines may offer their frequent flyers PreCheck® status and assign them a KTN as part of that process. Active duty military personnel may use their DoD identification number as their KTN. You may also apply for PreCheck® or Global Entry on your own. US citizens pay $85 for a five-year PreCheck® membership or $100 for a five-year Global Entry membership. (Tip: The nonrefundable fee must be paid whether or not you are approved for PreCheck® or Global Entry.)

How Do I Use My Known Traveler Number?

If you received your KTN through the TSA's PreCheck® program, you should add it to your reservation record every time you book a flight on a participating airline.

If you make a flight reservation through a travel agent, give the agent your KTN. You can also add the KTN yourself if you reserve your flight online or by telephone.  

Participating airlines, as of this writing, include Aeromexico, Air Canada, Alaska Airlines, Allegiant Air, American Airlines, Aruba Airlines, Avianca, Boutique Airlines, Cape Air, Delta Air Lines, Emirates, Etihad Airways, Frontier Airlines, Hawaiian Airlines, JetBlue Airways, Key Lime Air, Lufthansa, Miami Air International, OneJet, Seaborne Airlines, Southern Airways Express, Southwest Airlines, Spirit Airlines, Sun Country Airlines, Sunwing Airlines, United Airlines, Virgin America, Virgin Atlantic, West Jet and Xtra Airways.

If you obtained your KTN through the Global Entry program or by virtue of your status as an Armed Forces member, you should use it whenever you make an airline reservation, regardless of which airline you fly.

If I Have a Known Traveler Number, Why Don't I Get PreCheck® Status Every Time I Fly?

There are several reasons why you might not be able to use the PreCheck® screening lane, even though you have a KTN. For example:

Occasionally the TSA does not give PreCheck® status to enrolled travelers, as part of its effort to randomize security screening procedures.

The data you entered when you bought your ticket might not match the data on file with the TSA, DHS or DoD. Your first name, middle name, last name and date of birth must match exactly.

You may have entered your KTN incorrectly when you bought your ticket.

Your KTN might not be saved in your frequent flyer profile, or you may not have logged in to your frequent flyer account before you bought your ticket online.

If you bought your ticket through a travel agent or third party website, such as Expedia, your KTN might not have been passed along to your airline. The best way to correct this problem is to call your airline and make sure your KTN has been entered into your reservation record.

Do this before you check in for your flight.

You may not have noticed that you could not enter your KTN when you purchased your ticket online. This occasionally happens with online travel websites (third party websites). 

Once you have a KTN, you are supposed to use it. Always look for the KTN field when you buy an airline ticket online and contact your airline after you complete your purchase if you do not see it.

How to Resolve Known Traveler Number Problems

Double-check your travel documents (driver's license, government-issued photo ID and / or passport) to be sure your full name and birth date match the information you provided to the TSA or DHS.

Save your KTN in your frequent flyer account record(s).

Train yourself to look for the KTN field whenever you buy an airline ticket.

Call your airline before your check-in date to be sure your KTN has been added to your reservation record.

If you encounter problems at check-in or at the airport, contact the TSA as soon as possible to find out what happened. According to the Wall Street Journal, the TSA only retains PreCheck® data for three days after your flight, so you'll need to act quickly.