Ks no Sora Tobu Kikaitachi , Imaginary Flying Machines? is a 2002 Japanese animated short film produced by Studio Ghibli for their near exclusive use in the Ghibli Museum. It features director Hayao Miyazaki as the 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.
Source: Wikipedia