Great drawings. You took the current warships designs and joined them with a kind of spaceship look very well and convincingly.
Hey! I have an idea that may serve you! I also like the concept of airships. Large trasatlantic transports that fly without massive helium floaters.
Well, one not-yet posible technology that may serve you to explain how the hell this things stay in the air, is the "air-pressure reducer". Kind of the quanta effect (the one that make ufo's fly) but whitout the circle shape requisite.
What an "air-pressure reducer" does (and please, try to give me credit for it, JUST in the very improbable case I'm the first to think about it) is that it is a plate, fabric or large surface that uses electric or calorific energy to reduce the pressure of the air above it, just like a wing, but without the speed need.
Idealy, this machine, or part of the ship, does exactly the same thing a large wing does, but you don't need to move horizontaly in order to stay in the air. Its kind of an antigravity engine, but doesnt't funcion above the atmosfere, and doesn't uses fisical thrust like a turboreactor.
How the hell any machine can reduce the air pressure above it efficiently enough to elevate? I have no idea. But maybe a nano tecnology material, powered by electric power could do it. Also, you could invent a special material or metal that does that effect when you apply heat or some energy to it.
Its still a unfinished idea. But it has a lot of sci-fi posibilities. Have you heard about it? Are my hopes of being the first to think about it false? (a very, very, likely posibility...)