It has been years, but at one point I remember seeing a part of an anime on TV in which there was a lonely small house in the middle of a field on either a hill or a floating island. I remember the grass blowing in the wind.
It was clear the young siblings, boy and younger sister, were trying to escape or stay away from the flying ship? Magic may also have been involved? And I seem to remember the girl was more of a target?
Additional small details: The boy had black hair, the girl had blond hair. Their parents were absent/dead. There was some sort of "vilain" on board the flying ship, a young man. The emphasis on the "bad guy" was definitely there, it was an established, individual character.
What it is not: Howl's Moving Castle, it was definitely intended for a more mature audience than Howl's, drawn in a style that was only slightly different, definitely less childlike. Also not Castle in the Sky, more like Howl's than Castle in the Sky. The scene definitely resembled the proposed scene, but is not that one. There were no flowers in the field, mostly just grass.