Man this is a great post, I'm a big fan of science fiction. I really enjoy watching a show, to analyze how the thought future will be, I always keep looking at the design of common stuff.
I recently have watched Black mirror, and I think in some points they did a great approach to what could future look like.
I always remember The fifth Element and the flying cars you mention, and also my answer will be NO, we don't need flying cars, we are not gonna be all able to drive them, and it will be so expensive to coast by citizens. Anyway, I always try to imagine what will be the next "big invention" on this new era to get close to the futuristic old sci-fi designs.