Yes, if you want to use the TSA PreCheck benefits that come with your Global Entry membership, you must include your PASS ID (the 9-digit number on the back of your card) in the "Known Traveler Number" (KTN) field when booking your flight. In 2026, simply having the membership is not enough; the airline must transmit this number to the TSA's Secure Flight system during the "vetting" process before your boarding pass is issued. If you forget to add it during booking, you can usually add it later through the airline's app or at the check-in counter, but it must be done before the boarding pass is printed for the "TSA Pre✔" indicator to appear. It is a common mistake to leave this field blank, which results in having to wait in the standard security line despite being a trusted traveler.