Skidbladnir

In Norse mythology, Skidbladnir was Freyr's boat, built by the dwarf Dvalin, and taken from him by Loki.

This ship was so cunningly constructed that it could, when not in use, be folded so neatly that one could put in a pouch. When unfolded, it was of course full-sized, and could travel over both land and sea. In whatever direction it went, it always had a fair wind.