Which of the flightless birds has the largest wings?

After a bit of research, the largest wingspan is the common ostrich (Struthio camelus).

Though they cannot fly, these birds have a wingspan of between two and three meters (6.5-9.8 feet). They beat out the other flightless birds by quite a fair bit - emus and cassowaries have tiny ones, for example. Second place would be the South American rhea, whose wings are about 1.5 meters (5 feet).

The ostrich lives in a hot African climate and uses these wings for temperature regulation. They are also used as sails or rudders while the ostrich is running. They court the females of the species with the wings, and they can also serve as intimidation against animals that would want ostrich for dinner.

https://en.wikipedia.org/wiki/List_of_largest_birds#:~:text=The%20largest%20extant%20species%20of%20bird%20measured,living%20bird%2C%20averaging%201.4%20kg%20(3.1%20lb).