The Case Against Flying Cars
It's remarkable to contemplate how much of science fiction's vision for the future has already come true. But in some ways we have been left out in the cold in terms of the future we expected. The reason for the gap sometimes has more to do with what nature allows, than what we have the will to build.
I have just written a piece for The New York Times exploring why we don't have "air cars" and by this I mean the sci-fi flying vehicles of movies and books (not a car with wings and a propeller). The reason, I argue, we don't have "hovercars" and their ilk is that we have only no control over the force gravity (as compared with other forces).
To see what I'm saying consider this one fact. To reach the domains where gravity becomes quantum mechanical (that is what we'd need to explore to move toward controlling gravity) then we'd need to build a particle accelerator millions of light years long.
Good luck getting that funded.
When it comes to controlling gravity the way we control electromagneistm (which makes all your e-devices work), we are still at the level of dropping rocks on peoples heads.