This is the last battle of the "Sky Pirate" Shion Omar (described here) in her prized aerial galleon Empress of the Skies, against the Etrusean ironclad Air Destroyer Despina.
Levistone is buoyant in a dimension which is not directly observable, and provides similar resistance to a hull in the water; the lift is increased if it is heated, and Despina was the first leviship to use coal furnaces instead of wood-burning stoves, hence the trail of smoke from her underside.