Castle is the earlier of the two, and is convulsively, exuberantly imaginative, full of flying contraptions that should never work and other stunning bits of brain candy. It’s a full-on adventure story that reminds me somewhat of Tintin — but on shrooms.
Kiki is, for a movie about a young witch who flies around on her broom, somewhat more down to earth; like Spirited Away, it’s about, and mainly for, young girls — an animé Bildungsroman. It’s lighter and funnier, too. Two words: the cat. Voiced in the English version by the late Phil Hartman, the cat is a show-stealer.
In both films, Miyazaki, who is reportedly obsessed with flight, animates it very well: you can absolutely feel the wind when someone is in the air. Oh, he’s good.