tl:dr I built an airship that I wanted to use as a testbed for the replay mod and filming builds, but I think it can be improved but I'm not 100% sure how. I feel like there's a lot of empty space, but not sure what to fill it with. I feel like deck and maybe below-deck area are in need of more 'stuff' in particular. Pics and video below:
Other from the bigger balloon everyone is talking about, I would smooth out the hull with stairs and changing some blocks of the big chunks of wood to other wood types (i.e. spruce, spruce trapdoors and something like this) as large surfaces does not look very well in minecraft, lacking variety.
Same for the balloon itself, try to mix some other kind of white into that (quartz, bone blocks or concrete) and see what it looks better than a flat colour.