Many travelers ask How Do You Add TSA PreCheck to United Airlines? » It's a simple process that makes airport security faster and more convenient. After receiving your Known Traveler Number from the TSA, log into your United MileagePlus account and add the KTN to your profile. You can also enter it manually when booking a flight or update an existing reservation. With TSA PreCheck, eligible passengers enjoy quicker screening no need to remove shoes, belts, or laptops. United ensures a smooth travel experience by recognizing your PreCheck status, helping you save time and avoid long security lines.