[lachstar-x]

One of the issues with getting that high is that the higher you go, the less buoyancy the airships have, and you'd need bigger ships with more gas to haul the same loads. But the sky is very big, so it might just be an economics of scale problem

[clueless123]

In this case, ships will be heavily loaded on the way down (carrying heavy produce) and lightly loaded on the way up (carrying lighter products like medicine or high value manufactured goods)