Solarpunk technology

Blimps would have to somehow fit in. Having considerable air resistance, blimps cannot travel as fast. Being unable to travel as fast, they would fall behind at moving X people per hour - while a blimp makes one roundtrip, a jet aircraft would make multiple roundtrips.

Blimps are far worse than airships; the fundamental advantage of airships is that they scale up well (doubling the size nets you 8x the volume), which blimps just don't. And blimps are far less safe, due to their gas bags needing to be pressurized where airships' gas bags can be unpressurized. More specifically, if you puncture a pressurized gasbag, then its contents spray out due to the pressure, which in the context of hydrogen would mean it rapidly mixes itself into large amounts of hydroxygen just begging to explode, whereas unpressurized gasbags will just slowly diffuse hydrogen like piss in water. Still potentially dangerous, but far less so.

Weirdly, when it comes to cargo airshipping, airships are actually faster than cargo freight (not to be confused with parcel freight, which is what post (e.g. Amazon packages) uses). Cargo freight takes 4-5 days, which airships can easily beat via shipping point-to-point.