Learn About Known Traveler Numbers for Travel

What Are Known Traveler Numbers?

A Known Traveler Number (KTN) is a unique identification code that you can provide to airlines and the Transportation Security Administration (TSA) when booking flights. This nine-character code tells security screeners that you have already completed a background check and vetting process through one of several trusted traveler programs. The KTN acts as a shortcut through some airport security procedures by letting TSA officers know you've been pre-screened.

The concept of known traveler programs began in the early 2000s as airports and security agencies looked for ways to speed up screening for low-risk travelers while maintaining security standards. TSA created these programs to reduce wait times at security checkpoints while allowing screeners to focus more resources on unknown travelers. Today, millions of people use KTNs to move through airports more smoothly.

KTNs come from several different programs, each with its own requirements and benefits. The most common sources include TSA PreCheck, which is the domestic program; NEXUS, which covers U.S.-Canada travel; SENTRI, which covers U.S.-Mexico travel; and GLOBAL ENTRY, which includes international benefits. Each program vets members differently and offers distinct advantages depending on your travel patterns and destinations.

When you provide your KTN during flight booking, the airline sends this information to TSA before your flight. At the airport, TSA uses this number to identify you as a vetted traveler. Depending on which program you belong to, you may pass through standard security screening or, in some cases, get access to dedicated security lanes with shorter wait times. The system works because TSA has already verified your background information before you ever enter the airport.

Practical Takeaway: If you travel by air regularly, learning how to obtain and use a KTN can reduce your time spent waiting in security lines. Start by identifying which trusted traveler program matches your travel needs—domestic only, or international destinations—and then understand what that program requires.

How the TSA PreCheck Program Works

TSA PreCheck is the most widely used trusted traveler program in the United States. As of 2024, over 12 million people hold an active TSA PreCheck membership. This program screens travelers who fly domestically within the United States, and members receive a KTN they can use when booking flights. The program was designed to create a faster security experience for frequent domestic travelers who have undergone background checks.

To participate in TSA PreCheck, you must go through an in-person appointment at one of hundreds of enrollment centers located across the country. During this appointment, a TSA officer will verify your identity using government-issued documents, take your fingerprints for a background check, and collect biographical information. The background check examines criminal history, immigration records, and security databases. The entire appointment typically takes about 10 to 15 minutes, though wait times for appointments vary by location.

TSA PreCheck membership lasts five years from the date of your enrollment appointment. You will receive a Known Traveler Number (usually starting with the number "1") that you can use immediately. You can add this KTN to your frequent flyer accounts with airlines, your airline booking profiles, or enter it directly when booking tickets. When you arrive at the airport with your boarding pass showing your KTN, you may be directed to a TSA PreCheck security line.

In a TSA PreCheck lane, the security screening process changes in several ways. You can keep your shoes, light jacket, and belt on during screening. You can leave laptops and most liquids in your carry-on bag, which means you do not need to remove and separately scan these items. The line typically moves faster because fewer items need to be removed and scanned separately. However, TSA PreCheck does not guarantee you will avoid standard security procedures—TSA officers may still conduct additional screening if needed.

The program does charge a fee, which was $78 to $85 for a five-year membership as of 2024, though prices may change. Some credit cards offer reimbursement for this fee, and certain government employees, military members, and veterans may receive discounts. Many frequent travelers find the cost reasonable when divided across five years of travel.

Practical Takeaway: TSA PreCheck is useful if you take at least a few flights per year domestically. To use it, you need to schedule an in-person enrollment appointment, provide identification and fingerprints, pass a background check, and receive your KTN. You can then add this number to your airline bookings to potentially access faster security screening.

Understanding Global Entry and International Programs

GLOBAL ENTRY is a trusted traveler program that extends benefits beyond domestic flights to international travel. Members of GLOBAL ENTRY receive a KTN and can use expedited screening when returning to the United States from overseas airports. The program includes TSA PreCheck benefits for domestic flights, making it a comprehensive option for people who travel internationally multiple times per year.

GLOBAL ENTRY members returning to the United States from foreign airports can use automated kiosks to process their entry instead of standing in long customs and border protection lines. At these kiosks, you scan your passport, answer security questions, and take a photo—a process that typically takes just a few minutes. After kiosk processing, you proceed to baggage claim and exit, having bypassed the traditional customs line. This benefit alone can save 30 minutes to over an hour on international returns, depending on airport traffic.

The cost of GLOBAL ENTRY is $100 for five years as of 2024. Like TSA PreCheck, the enrollment process requires an in-person appointment where you provide identification, fingerprints, and background information. Some premium credit cards reimburse the GLOBAL ENTRY fee, and some people find this reimbursement makes the program cost-neutral. You receive a separate GLOBAL ENTRY KTN and a physical card that you can carry.

For travelers focused on specific borders, two other programs may be more suitable. NEXUS is designed for frequent travelers between the United States and Canada and costs $50 for five years. SENTRI serves travelers between the United States and Mexico and also costs $50 for five years. Both programs include TSA PreCheck benefits and offer their own trusted traveler numbers. NEXUS members can use dedicated lanes at U.S.-Canada border crossings, and SENTRI members can use dedicated lanes at U.S.-Mexico border crossings.

All of these programs require background checks and vetting processes. GLOBAL ENTRY involves interviews conducted by U.S. Customs and Border Protection, while NEXUS and SENTRI have their own specific vetting procedures. The background checks for all programs examine your immigration history, criminal background, and other security factors. Membership can be revoked if circumstances change or if you violate program rules.

Practical Takeaway: If you travel internationally several times per year, understanding GLOBAL ENTRY and border-specific programs like NEXUS or SENTRI can help you choose the right trusted traveler program for your travel patterns. Each program requires enrollment, provides a KTN, and offers different benefits depending on your destinations.

How to Add Your KTN to Flight Bookings

Once you receive your Known Traveler Number from any trusted traveler program, you need to provide it to airlines so that TSA can see it connected to your flight. There are several ways to add your KTN to your flight bookings, and understanding each method ensures you receive the full benefits of your membership.

The simplest method is to add your KTN to your frequent flyer account with each airline you use. Most major U.S. airlines—including American, Delta, United, Southwest, and others—allow you to store your KTN in your online account profile under a section labeled "Trusted Traveler Information" or similar language. Once you enter your KTN there, the airline automatically includes it on all future bookings made under that account. This means you do not need to manually enter it each time you book a ticket.

If you are booking a flight without using a frequent flyer account, or if you book through a third-party travel website, you can usually enter your KTN directly into the booking form. During the flight booking process, you will typically see a field asking for "TSA Known Traveler Number" or "Trusted Traveler Information." Entering your number at this point ensures it appears on your boarding pass. The number should be nine characters long and may include letters and numbers.

Your KTN should appear on your boarding pass