Also important to note not just which airports have a Centurion lounge, but which TERMINALS they're located in. If you fly carriers like JetBlue at JFK out of Terminal 5 (just as one example), the Centurion Lounge in T4 is virtually useless since it's such a hassle to access. You would have to look up which terminals CL are located in, along with the carriers that you usually fly and see if they match up.