Kuusou no Sora Tobu Kikaitachi

Animated 2002 short film produced by Studio Ghibli for their near exclusive use in the Ghibli Museum. It features famous director Miyazaki Hayao himself as narrator (in the form of a humanoid pig, reminiscent of Porco from Porco Rosso), telling the story of flight and the many machines imagined to achieve it.

Note: The film could also be seen on the in-flight entertainment system used by Japan Airlines.

(Source: AniDB)