To answer What is tsa precheck more specifically, it’s a program managed by the Transportation Security Administration (TSA) in the U.S. TSA PreCheck is available at more than 200 airports and with over 85 airlines. The goal is to offer a streamlined experience for frequent and trusted travelers. After applying and going through a background check, approved passengers are given a Known Traveler Number (KTN) that they enter when booking flights. This number allows them access to dedicated TSA PreCheck lanes at security checkpoints.