What is the name of Aang's sky bison?

Aang’s sky bison is named Appa. Appa is Aang’s lifelong animal companion, transportation, and trusted friend throughout Avatar: The Last Airbender.

Appa belongs to the sky bison species, enormous flying mammals associated with the Air Nomads. In the series, sky bison fly through a combination of their natural abilities and airbending, using their broad tails to steer through air currents. Air Nomad children traditionally receive a sky bison as a lifelong companion, and Aang met Appa when they were both young.

Appa carries Aang and his friends across the world during their journey to restore balance. His disappearance and captivity in the episode “Appa’s Lost Days” becomes one of the series’ most emotional storylines. Appa is also described as the last known living sky bison, making him important not only to Aang but to the survival of Air Nomad culture.

Roku was Aang’s predecessor as Avatar, Naga is Korra’s polar bear dog, and Momo is Aang’s winged lemur companion. Those names belong to other important characters, but Appa is the sky bison.