The hover cars in 'Back to the Future 2' might actually be possible. It all comes down to magnets.

Your roller doors might be smooth, but they'll never be this smooth. Californian company Hover Doors uses permanent magnets to float heavy sliding doors as if they're mag-lev monorails, for super ...

With the magnets supercooled, they "slow down", and can be positioned in predictable ways, allowing the board to exist in a suspended state above the ground. See All 12 Photos ...