Sounds a lot like the train during Apolopitic (SP?) times, on Earth, movie & series- ‘Snowpeircer’ (SP?). While trying find the spelling for previously mentioned title, on DuckDuckGo, I found ‘The Last Train’ funny how there are more such stories, than just ‘Snowpiercer’ (SP?, LOL, I will get right one time, LOL), using old form of transportation & not like a flying city. Not saying trains are outdated or anything, just not the latest thing. I am loving the idea of flying vehicles, that are: as green as possible, not owned, but shared & driverless, unless choose to drive.