How to Add TSA PreCheck to Your Allegiant Air Account

Link Your TSA PreCheck Number to Allegiant During Booking

You add TSA PreCheck to Allegiant by entering your Known Traveler Number (KTN) when you book a flight or manage an existing reservation. Allegiant does not have a separate account setting where you store your TSA PreCheck permanently—you enter it each time you book, or you can add it to a reservation you have already made.

The Known Traveler Number is a nine-character code that TSA issues when you enroll in PreCheck. You receive it by email after your enrollment is complete and your background check clears. If you have already enrolled in TSA PreCheck but cannot find your KTN, check your TSA PreCheck approval email or log into the TSA website to retrieve it.

When you book on Allegiant's website, you will see a field labeled "Known Traveler Number" or "KTN" in the passenger information section. Enter your nine-character code exactly as it appears on your TSA PreCheck documentation. Do not add spaces or dashes unless they are part of the actual number.

Key Takeaways

Your Known Traveler Number is a nine-character code issued by TSA when your PreCheck enrollment is approved, sent to you by email.
Enter your KTN in the passenger information section when booking a flight on Allegiant's website or mobile app.
You can add your KTN to an existing reservation through "Manage My Booking" if you forgot to include it during checkout.
Allegiant does not store your KTN in your account permanently, so you will need to enter it for each new booking.
If your KTN does not appear on your boarding pass, contact Allegiant customer service before your flight to may support it is linked correctly.

Add Your KTN to a Reservation You Already Made

If you booked a flight without entering your TSA PreCheck number, you can add it later through Allegiant's "Manage My Booking" tool. Go to Allegiant's website, select "Manage My Booking," and enter your confirmation number and last name. Once you access your reservation, look for the passenger details section and find the field for Known Traveler Number or KTN.

Enter your nine-character code and save the changes. Allegiant will update your reservation, and your KTN should appear on your boarding pass within a few hours. Check your boarding pass online to confirm the number is there before you arrive at the airport. If the KTN still does not show up after several hours, contact Allegiant's customer service line to verify it was saved correctly.

Where to Find Your Known Traveler Number

Your KTN appears in the approval email TSA sends after your PreCheck enrollment is complete. The email subject line usually says "TSA PreCheck process Status" or similar. Search your email inbox for messages from TSA or check your spam folder if you cannot find it.

If you cannot locate the email, log into the TSA PreCheck website using the account you created during enrollment. Your KTN will be displayed in your account dashboard. You can also call TSA's PreCheck customer service line at 1-855-347-8371 to request your number, though you will need to verify your identity with information from your process.

What Happens When Your KTN Is Linked Correctly

When your KTN is successfully linked to your Allegiant reservation, it will print on your boarding pass in a specific location. Most airlines print the KTN near the barcode or in the top corner of the pass. This tells TSA officers at security that you are enrolled in PreCheck and may be able to access for expedited screening.

At the security checkpoint, show your boarding pass and a valid ID. TSA officers will scan your pass and see your PreCheck status. You will then proceed to a PreCheck security lane, where you can leave your shoes, belt, and light jacket on, keep your laptop and liquids in your carry-on bag, and move through screening faster than standard passengers.

Common Mistakes When Entering Your KTN

The most common error is typing your KTN incorrectly. The nine-character code must match exactly what TSA issued—do not add spaces, dashes, or extra characters. Copy and paste your KTN from your approval email or TSA account into the booking field to avoid typos.

Another mistake is confusing your KTN with other travel numbers. Your TSA PreCheck number is different from your Global Entry number, NEXUS number, or frequent flyer number. Make sure you are entering the correct nine-character code for TSA PreCheck specifically. If you are unsure which number is your KTN, check your TSA PreCheck approval email or log into your TSA account to confirm.

Some travelers enter their KTN but do not see it on their boarding pass and assume it did not work. Boarding passes can take a few hours to update after you add your KTN to a reservation. Check again the day before your flight or a few hours after you make the change. If it still does not appear, contact Allegiant before you go to the airport.

Entering Your KTN on the Allegiant Mobile App

You can also enter your KTN when booking through the Allegiant mobile app. During the passenger information step, tap the field for Known Traveler Number and type your nine-character code. The process is the same as on the website—enter it exactly as TSA issued it, with no extra spaces or characters.

If you are managing an existing booking through the app, open "Manage My Booking," find your reservation, and look for the passenger details section. Tap the KTN field and enter your number. Save your changes, and your boarding pass should update within a few hours. You can view your updated boarding pass in the app to confirm your KTN is there.

What to Do If Your KTN Does Not Appear on Your Boarding Pass

If you entered your KTN correctly but it does not show on your boarding pass after several hours, contact Allegiant's customer service. Have your confirmation number and KTN ready when you call. Allegiant's agents can manually verify that your KTN is linked to your reservation and troubleshoot why it is not printing on your pass.

Call Allegiant at 1-702-505-8888 or use the chat feature on their website. Explain that you added your TSA PreCheck number to your reservation but it is not appearing on your boarding pass. The agent can check your reservation in their system and either correct the entry or escalate the issue if there is a technical problem. It is best to resolve this before you arrive at the airport so there are no delays at security.

Frequently Asked Questions

Do I have to enter my KTN every time I book with Allegiant?

Yes. Allegiant does not store your KTN in your account permanently. You must enter it during booking or add it to your reservation afterward through "Manage My Booking." Some other airlines allow you to save your KTN to your frequent flyer account, but Allegiant requires you to enter it for each flight.

What if I do not have my TSA PreCheck number yet?

You cannot add a KTN to your Allegiant booking if you have not enrolled in TSA PreCheck. You must complete your PreCheck enrollment, pass the background check, and receive your approval email with your KTN before you can link it to a flight. If you are planning to fly soon and do not have PreCheck yet, you can book your flight without a KTN and add it later if your enrollment is approved in time.

Can I use someone else's KTN on my Allegiant reservation?

No. Your KTN must match the name on your boarding pass and ID. TSA PreCheck is tied to your identity, and using someone else's number will cause problems at security. Each passenger must have their own KTN linked to their own reservation.

Will adding my KTN to Allegiant cost extra?

No. Linking your TSA PreCheck number to your Allegiant reservation is free. You pay for TSA PreCheck enrollment separately (the fee is currently $78 to $85 for five years, depending on your location), but adding your KTN to any airline booking costs nothing.

What if my boarding pass shows my KTN but I am not sent to a PreCheck line at security?

TSA officers have the final say on whether you go through a PreCheck lane. Even if your KTN is on your pass, factors like airport traffic, staffing, or random selection can mean you go through a standard security line instead. This is normal and does not mean your PreCheck is not working. Your KTN is still valid for future flights.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.