They're the companions of my people, the air nomads! We each bond with a sky bison for life when we're young. They're the original Airbenders and use airbending to fly around. [He takes a moment to glance offscreen.] I can actually give you a look at him right now!

[Aang holds the journal out the window of the house; on the lawn, Appa can be seen lazing in the sunlight.]