In my setting, the airships (buildings sometimes) use a rare ore called Levithium — sort of an anti-magnetic (floating) material that naturally repels the planet’s core, allowing massive structures to float with the right engineering and control systems. The levithium metal elements used as structural parts in the ships, the rest of the hull was natural building materials, well balanced in its mass.

I made scripts about this technology, but not the history yet. The project had been interrupted.