Spirits of the Air, Gremlins of the Clouds

Spirits of the Air, Gremlins of the Clouds is a movie starring Michael Lake, Melissa Davis, and Norman Boyd. Brother and sister endure alone together in a post-apocalyptic Outback until the sudden arrival of a stranger.
A religious brother and sister endure alone together in the post-apocalyptic Outback, until the sudden arrival of a stranger who helps them build a crude plane to fly out of the desert.