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 this idea, the views could be fantastic. The article mentions the problem of prevailing winds - so plan circular trips following the trade winds, as sailing ships used to do. For example, from Spain to the Carribbean, up the coast, back further north (recall - global empires were run without plane-speed, people traveled the world and had interesting lives). Complement the network with sleeper trains overland where practical - for example train down the african coast, down brazilian coast, airship to cross narrowest gap). 48 hours transatlantic, that's nothing compared to a week or more on trans-siberian (although a modern tgv could do Paris-Shanghai in about 48 hrs - if political will instead of obstacles).
Side thought - is there an issue regarding supply of Helium (or energy cost to separate it ...?) if scaling this up?
It sounds like a wonderful idea. The need to cross the globe in a day is a made up bit of nonsense anyway. Why? Just why?