> In the US you have this TSA precheck that you need to have an appointment to set up? I think it's just a one-time appointment to get enrolled in precheck. Wh

> In the US you have this TSA precheck that you need to have an appointment to set up? I think it's just a one-time appointment to get enrolled in precheck. While flying, you just select a different (in theory speedier) line. "CLEAR" is weirder. They're a private company, for one; AIUI, they get you through the lines quicker, and they do the document check portion¹ of the TSA flow, but not the security screening; vs. the TSA Precheck will result in a lighter security screen portion. (They're expensive, so I've never considered them.) ¹the typical TSA flow is: 1) huge line, 2) "document check" where your boarding pass & ID are inspected, 3) small line, 4) baggage xray + (body scanner || pat down)