Looking for a late 80's/early 90's cartoon children's movie...
I must have seen this movie a hundred times and I have no clue what it is. The characters were creatures of some sort - mice, hedgehogs, something. The little sister of one of the mice, we'll call them for clarity's sake, got really sick and all the mice took her to an old woman mouse in the woods who lived in a tree, I think? The old woman mouse gave her some medicine but told the other mice they had to go find... something, medicine, maybe to cure her, and so they set off. Somewhere in the movie, later on in the middle, maybe, humans came in the forest and started gassing the place with poison gas and the fattest mouse couldn't run fast enough and got captured. In the end they built an airship out of a walnut, and maybe leaves for propellers, I believe, and... sailed away? Please. Please remember. Someone. And no, it is not The Rats of NIMH.