FFO Name: Levistone
"Mysterious rock that floats in the air."
You'll find the Floater in the Ice Cave. It's used to make the airship fly.
Stand in the Ryukahn Desert and use the Floater to raise the airship from beneath the sand.
In the Japanese version the Floater is called the Floating Stone. I don't know if it was intentional, but the Japanese word for "floating" also sounds like the Japanese word for "winter".