Agreed. I'm not a big fan of Twitter, but flying cars don't exist for a reason. Now self-driving cars, those are interesting. Guess who's working on them? Google.

Self-flying cars?

Actually flying cars exist now and have been approved for use by all requisite governmental agencies.

http://www.terrafugia.com/

It seemed to work just fine in the fifth element!

What about sky cities like the Ultima tower?