Priority lines gets you a shorter line. Precheck gets you a less invasive screening procedure. Priority lines exist because the airport, rather than the TSA co

Priority lines gets you a shorter line. Precheck gets you a less invasive screening procedure. Priority lines exist because the airport, rather than the TSA controls the lines. The airport tries to do what the airlines want, and the airlines want people who pay them extra to have a better experience. This is arguably broken, but it's not really the TSA's fault.