-Hot-Air Ballon: small and relatively slow, with little to no cargo space, but requiring only fuel (no gas) - basically an early(ish)-game scouting and exploration vehicle. No landing pad required.
-The Conglomerate: larger but still slow, looking like a bunch of hot-air ballons strapped together like a raft (and indeed requiring several of them in its recipe), still requiring only fuel but now with a decentish cargo capacity. Targetting the midgame, this would be the first aerial trading vessel: using tier 1 landing pads (smaller, ramshacle versions of what I described above, would provide fuel but not gas), routes could be established for the automated transport of goods (it would be so slow compared to trains that these would be the preferred alternative unless you wanted to carry stuff across the middle of a very long and narrow body of water (and before you say landfill, some of us like our virtual procedurally generated landscapes in their natural form
), so it would probably see use mostly as a way for the player to carry materials somewhere to establish outposts).-The Scout: mid to late game exploration vessel: very fast but with little to no cargo capacity and without the ability to set automated transport routes - it would require gas as well as fuel, and so would occasionally have to dock with a tier 2 landing structure. This would allow for fast exploration.
-Almalexia-Class First-Rate Airship-of-the-Line (hehe): the top-tier vessel outlined in the first paragraph; significantly faster than the conglomerate but significantly slower than a train; massive cargo capacity but also far leakier than the scout. Possibly capable of fitting potent armament at the cost of cargo slots (maybe tank guns on the broadsides?).
The first two would only become forcibly grounded if they ran out of fuel (and thus of the ability to generate hot air); buoyancy loss for gas vessels is already explained in the first paragraph.
The hot-air balloon would be hand-craftable, the conglomerate would be built by a tier 1 landing station and the other two would require a tier 2.
In order for to allow finer customisability of routes (and, crucially, to avoid clusters of enemies), waypoints would be a useful thing to include, so the airships on automatic mode wouldn't just go blindly in straight lines (also: waypoints for trains, wouldn't that be neat?).
I realise the existing vehicles (car, tank, train) already allow for some of this functionality, but now all, and isn't veriety nice?
