Because I've done a few airship paintings people occasionally ask me to design some for them. My airships for Gnemo are based on what would be plausible for the level of technology of that world but with the expectations that that world, although obeying the same physics as ours, would still be different. For example they might have access to a strong lightweight material that is more difficult or too expensive to acquire on our planet.
However, when someone else ask me to design something they have their own rules. Sometimes the parameters are wider and sometimes they're narrower. Giant ironclad aircraft carrying battle-airships seem pretty impossible to me. I can't come up with a plausible explanation for it but then I avoid changing physical laws unless I call it magic. Because of that these airships could never fly in the world I invented. Actually, they won't fly anywhere because they weren't quite right. These were just quick sketches to see if I understood what was wanted. I didn't. (And that's why I can show them to you.) I was thinking too big.
Speaking of Gnemo, I've got a new post there. It's a bit more finished than this drawing: Gnemo's Sketchbook