I could swear I've seen illustrations of such concepts. In the same theme as circular runways and having runways balanced across the tops of city skyscrapers.

I could swear I've seen illustrations of such concepts. In the same theme as circular runways and having runways balanced across the tops of city skyscrapers. The "moving platforms" concept seems to come up quite often, ala https://www.youtube.com/watch?v=MlhuHmVn4Ss https://www.youtube.com/watch?v=MlhuHmVn4Ss