Um, Southwest participates in the IATA clearing house. You put up the wrong list. Here is the right one: https://www.iata.org/contentassets/82a24c7a736142b6bd18

Um, Southwest participates in the IATA clearing house. You put up the wrong list. Here is the right one: https://www.iata.org/contentassets/82a24c7a736142b6bd18e20f77dcef60/ich-members.pdf https://www.iata.org/contentassets/82a24c7a736142b6bd18e20f7... And now for some industry education. You can participate without being an IATA member. Southwest likely started when they started flying internationally in 2014. You practically can't be an airline with international flights without participating. IATA runs the global clearinghouse. Notably, IATA does not run the clearinghouse for US domestic (and for foreign airline tickets purchased in the US.) That's ARC (Airline Reporting Corporation.) Southwest is also a member there.