Miryi shonen wa sora o tonda (1986)

Milly and Louis, and their recently-widowed mom, Charlene, move to a new neighborhood. Once there, they all deal with a variety of personal problems, but Milly finds a friend in Eric, her autistic next door neighbor. Eric has a fascination with flight, and as the story progresses, he exerts an enthralling force of change on all those around him.