Saw this article over on the solarpunk subreddit and wanted to bring it over here with my own opinion attached.
For being a near-zero way to travel in the air it's solar, but the reasons the author criticizes solar-electric propelled airships make it punk. The issues pointed out by the author - slow travel time, lower passenger counts, and windows of time for viable travel, a need for sleepers - could also be seen as its strengths.
For one, slow travel time and lower passenger counts make it a lot easier to meet and connect with strangers with little social risk. They also wouldn't need sleepers. With tight spaces like that, they're less comfortable than economy. My wife and I took a long distance train here in the U.S. (which has its own issues), but we loved the social interaction and actually preferred our economy seats over the sleepers. Two years later, we still like to chat about some of the folks we met and speculate on how they're doing.
The long transit time and specific travel windows would force people to rethink how badly they actually wanted to travel overseas and consider a more local scope. If that's not solarpunk...
I like the reactor idea. It'd also be a huge boon for the medical field, since helium is necessary for some devices and is currently a limited resource.
There's also the option to just use hydrogen, since you can produce it with electricity and water. Hydrogen gets better lift, and doesn't require petroleum-style drilling. It's flammable, as we saw in the past, but with modern engineering, modern materials, non-conductive pressure vessels, emergency release valves, no ignition sources or sparks in proximity, it seems like it could be done pretty safely. Modern aviation has a lot of problems but it is, I think, admirably safety-focussed, in everything from engineering to operation. I think solarpunk is very much about picking and choosing which parts of our society to keep and which to reexamine to see if they can be done better. Today's aviation safety seems very much worth keeping to me - I think they could find ways to do hydrogen airships safely.
I suspect the impact of train tracks on wildlife would be less than the current highway system, but could also be mitigated via animal overpasses and by raising the tracks on bridges or over tunnels.
Except those doors and engines on the 737 MAX. I've always thought hydrogen could be made to work in the 21st century. It's been 100-years... surely something must be better than doped cotton.