How Do You Add TSA PreCheck® to Southwest Airlines? by obtaining your Known Traveler Number (KTN) and enrolling in TSA PreCheck® before adding it to your Southwest Airlines trips. Next, sign into your Rapid Rewards account with Southwest Airlines, go to your profile settings, and input your KTN in the Secure Flight Passenger Data section. When making travel arrangements with Southwest Airlines, make sure your KTN is included in order to take advantage of expedited security screening at select airports.