Actually, the DeLorean that Mr. Riese is trying to build is registered as a boat and can only be drive around San Francisco Bay. It can hover on any flat surface and doesn't come with certain pesky features of traditional cars like breaks.
Well, at least there were some predictions from that movie that came true such as video conferencing and ubiquitous advertising. Sadly, the flying cars are still cost prohibitive. I'm hoping Mr. Riese, if he is successful with his flying car, will work on Mr. Fusion next.