Another spoiler from Book 2. As the plot moves along, I have added some cool details to the Airship Divinity. It is actually a flying aircraft carrier and the concealed deck is actually a flight deck. The Ministry thought that this unknown part of the airship was a weapons system of some sort and it turns out they were right. The Firebat is a one person fighter that is armed with a .58 caliber Gatling gun.
Since the gun is fixed, it requires the pilot to maneuver the flying machine to aim the gun for an attack.