Yeah, reading it, I definitely mixed the two. The first one I was thinking of for sure had a lengthy very sci-fi set-and-setting exposition where it explained that people flew around in hovering vehicles and their legs had atrophied. I can't remember the plot or anything that happened in the story, though, only that, so I think I just imagined that it had the plot of this Bradbury story. I've been wondering about it for a long time... I read it over 40 years ago and it was in a collection of stories probably published in the 60s.