The phrase "standby list" refers to a waiting list or queue of people who are ready to take a specific action or receive a service, but have not yet been given the opportunity. They are poised and prepared to be called upon when needed.
Sentences with «standby list»
It's easy to search for award flights, find information, look at the upgrade standby list, and so on. (travelcodex.com)
If an upgrade is still not confirmed when you check in, your pending upgrade request will be automatically added to the airport standby list for a potential upgrade at the gate before you board. (delta.com)
If the courtesy waitlist does not clear, it will expire 24 hours before itinerary departure, and you will automatically be added to the airport upgrade standby list upon check - in. (united.com)