The building that Evey's flying parallel to has been seen before at least once. You can see it as part of the skyline at the beginning of Chapter 9. Cape Tower is a supertall skyscraper that actually billows like a cape in the wind. It's an amazing feat of engineering that is more of a novelty than a useful building. It is definitely one of those structures that seemed like a cool idea at the time but the actual thing itself leaves much to be desired. Tourists seem to love it though and having an office there is consider a mark of prestige. So it's not all bad.