Make sure you have a TSA Known Traveler Number (KTN) before adding TSA PreCheck to your Japan Airlines (JAL) reservation. How To Add Tsa Precheck To Japan Airlines after obtaining it, access your JAL account by logging in or go to the Manage Booking part of their website. In the space intended for TSA PreCheck, enter your KTN. As an alternative, you can contact JAL customer support for assistance or offer your KTN while making a flight reservation. To ensure that you are qualified for expedited security screening at select U.S. airports, remember to include the number before checking in.