Valkyrien Skies is a Minecraft mod. But not just any Minecraft mod. Valkyrien Skies aims to be the Minecraft ships mod everybody's always wanted. Block interactions, custom collision for walking on ships, mod compatibility and plenty of other features as well.
Truthfully a lot of the problems other ship mods have claimed to be as impossible and impractical are indeed quite solvable, and VS remains as proof of that. A fully integrated custom control system is in the works, but for now the mod is stable enough to be used as a physics sandbox built into Minecraft.
Valkyrien Skies has a large community, which can be found on several platforms.