It appears that you can no longer put your name on the standby list at the airport unless you are PlatPro or EXP. You have to use the app or website. Can you request standby the day before? What happens if you request to be put on the standby list for an earlier flight but are not at the airport when the standby list is cleared? Do you lose your confirmed seat on the later flight? I'm have AA LT Plat for more than 10 years and BA Gold.
Thanks...