How to Add Your Known Traveler Number to Flight Bookings

Where to enter your Known Traveler Number

You enter your Known Traveler Number (KTN) in the passenger details section when you book a flight, not after. Most airlines let you add it during the initial booking or edit it in your reservation up to 24 hours before departure. The field is usually labeled "Known Traveler Number," "KTN," or sometimes "TSA PreCheck Number" — different airlines use different names for the same thing.

If you book through an airline website directly, look for the field in the "Passenger Information" or "Additional Details" section. If you book through a third-party site like Kayak, Expedia, or Google Flights, the option may not appear at all — you will need to complete the booking, then log into the airline's website and add the KTN to your reservation there. Some third-party sites do include the field, but it varies by site and airline.

You can also call the airline's reservations line and give them your KTN over the phone. This is slower but guarantees it gets attached to your record. Write down your confirmation number before you call so the agent can find your booking quickly.

Key Takeaways

• Enter your KTN during booking in the passenger details section, or add it to an existing reservation through the airline website up to 24 hours before departure.
• Third-party booking sites often do not have a KTN field, so you may need to book first and then add it through the airline's website afterward.
• Your KTN is a 10-digit number that starts with a letter and appears on your TSA PreCheck approval notice or in your TSA PreCheck account online.
• The airline must receive your KTN before you check in; adding it at the airport is too late to get TSA PreCheck screening at that trip.
• If you forget to add your KTN, you can still go through standard security, but you will not receive expedited screening even though you hold an active TSA PreCheck membership.

Finding your Known Traveler Number

Your KTN appears on the approval notice you received when TSA PreCheck was first granted to you. If you no longer have that letter, log into your TSA PreCheck account at universalenroll.dhs.gov. Click "View My Application" and your KTN will be displayed on the status page. You can also find it by searching your email for messages from TSA or Universal Enrollment Services — the approval email contains your number.

If you have Global Entry, your KTN is the same number. If you have NEXUS or SENTRI (the Canadian and Mexican trusted traveler programs), you have a separate KTN for each program, and you should use the one that matches the airline you are flying. For domestic U.S. flights, use your TSA PreCheck KTN.

Write your KTN down and keep it somewhere accessible — your phone notes, your wallet, or a password manager. You will enter it every time you book a flight for the next five years (the length of a TSA PreCheck membership).

What happens after you add your KTN

Once the airline receives your KTN, it stays attached to your reservation. When you check in online or at the airport, your boarding pass will show a TSA PreCheck indicator — usually a checkmark, a "TSA" logo, or the words "TSA PreCheck" printed on it. This tells the TSA officer at security that you are enrolled and may be able to access for expedited screening.

At the security checkpoint, you will go through a dedicated TSA PreCheck lane (if the airport has one — smaller airports may not). You keep your shoes, belt, and light jacket on; you leave your laptop and liquids in your bag; and the line typically moves faster because fewer people are in it. The screening is still thorough, but the process is streamlined.

If your boarding pass does not show the TSA PreCheck indicator, tell the officer before you start removing items. Sometimes the airline fails to transmit the KTN correctly, and the officer can manually verify your enrollment in the TSA system. This happens rarely, but it is worth mentioning rather than assuming the system worked.

Adding your KTN to airline frequent flyer accounts

Most airlines also let you store your KTN in your frequent flyer profile. This is optional but saves time on future bookings — the airline will automatically pull your KTN from your profile and attach it to every reservation you make under that account. To do this, log into your frequent flyer account, find the "Profile" or "Personal Information" section, and look for a field labeled "Known Traveler Number" or "TSA PreCheck."

Storing your KTN in your frequent flyer profile does not replace entering it during booking — it just pre-fills the field for you. If you book as a guest (without logging into your frequent flyer account), you will still need to enter your KTN manually. If you book multiple passengers on one reservation, make sure each person's KTN is entered separately; the system will not auto-populate for traveling companions.

Fixing a KTN that was entered wrong

If you entered your KTN incorrectly during booking, you can edit it through the airline website as long as you do so before 24 hours before departure. Log into your reservation using your confirmation number and last name, find the passenger details section, and update the KTN field. Save the changes and you are done.

If you realize the error less than 24 hours before departure, call the airline directly. Explain that you need to correct your KTN on your reservation. The agent can usually fix it over the phone, though some airlines may charge a change fee depending on their policy. It is worth calling — flying without your KTN attached means you will not get TSA PreCheck screening, even though you paid for membership.

If you arrive at the airport and discover the error, tell the TSA officer at the checkpoint. They can look up your enrollment status in the TSA system manually, though this takes extra time and is not may provide to work. The faster solution is to prevent the error in the first place by double-checking your KTN before you submit your booking.

When your KTN changes or expires

Your KTN does not change during your five-year TSA PreCheck membership. If you renew your membership after it expires, TSA will issue you a new KTN. You will need to update it in all your airline frequent flyer profiles and use the new number for all future bookings.

If you lose your TSA PreCheck membership (because it expired and you did not renew, or because TSA revoked it), your old KTN will no longer work. Do not enter an expired KTN on new bookings — the airline will reject it or the TSA will not recognize it at the checkpoint. If you want to keep using TSA PreCheck, you will need to renew your membership and receive a new KTN.

Different airlines, different processes

Most major U.S. airlines (United, American, Delta, Southwest, JetBlue, Alaska, Spirit, Frontier) all accept KTN entries and display TSA PreCheck on your boarding pass the same way. The field location and label may differ slightly, but the process is consistent: enter during booking or add it to your reservation afterward.

International airlines flying to and from the U.S. also accept KTN entries for domestic U.S. flights. If you are flying internationally, check the airline's website to see whether they have a KTN field — some do, some do not. If they do not, you can still use TSA PreCheck if you are a U.S. citizen or permanent resident, but you will need to tell the TSA officer at the checkpoint that you are enrolled. Bring your TSA PreCheck approval notice or a printout of your enrollment status as proof.

Frequently Asked Questions

Do I have to add my KTN every time I book a flight?

Yes, unless you store your KTN in your airline frequent flyer profile, in which case it will auto-populate when you book under that account. If you book as a guest or through a third-party site, you will need to enter it manually each time or add it to your reservation after booking.

What if I book a flight for someone else — do I use their KTN or mine?

You use their KTN, not yours. Each passenger needs their own KTN entered in their own name on the reservation. If you are booking for a family member or colleague, ask them for their KTN and enter it in their passenger details section.

Can I add my KTN after I check in online?

No. You must add your KTN before you check in — either during booking or by editing your reservation up to 24 hours before departure. Once you check in, your boarding pass is generated and locked. If you forgot to add it before checking in, you can still tell the TSA officer at security, but they may not be able to verify your enrollment in time.

What if the airline says my KTN is invalid?

Double-check that you entered it correctly — KTNs are 10 characters, usually starting with a letter. If it is correct and the airline still rejects it, your TSA PreCheck membership may have expired or been revoked. Log into your TSA PreCheck account at universalenroll.dhs.gov to confirm your membership status. If it is active, contact TSA directly at 866-289-9673 to verify your KTN.

Do I need to add my KTN if I have Global Entry?

Yes. Global Entry includes TSA PreCheck benefits, but you still need to add your KTN to your flight reservation to receive expedited screening. Your Global Entry KTN is the same number you would use for TSA PreCheck alone.