Elon Musk is a titan of tech innovation. He has made the electric car sexy again and revolutionized the solar-electricity market, and he also has plans for a Mars mission to set up an off-Earth colony of humans.

For all Musk's futuristic prowess, though, he has not given us that enduring pipe dream of the future: a flying car.

Why isn't this awesome future we've been promised happening?

That's what Neil deGrasse Tyson wondered when the astrophysicist got the chance to interview Musk for the March 22 episode of Tyson's StarTalk Radio podcast.

"Of course what we all really want is flying cars," Tyson said. Here's how Musk responded:

I'm debating, like, should there be flying cars or shouldn't there be flying cars? I'm of two minds on that.

If there are flying cars, then, well, obviously then you have added this additional dimension where a car could potentially fall on your head and would be susceptible to weather. And of course you will have to have a flying car that — where it will be like on autopilot, because otherwise forget it.

It's got to be autopilot, but even on autopilot, and even if you've got redundant motors and blades, you are still going from near zero chance of something falling on your head to something greater than that.

And there's also the noise challenge ...

Something that I do think that would help a lot in cities is more tunnels, essentially with flying cars you are talking about going 3D. And there's a fundamental flaw with cities where you've got dense office buildings and apartment buildings and duplexes and they are operating on three dimensions then you go down to the street and suddenly it's two dimensional ...

I think if you were to extrapolate that to cars and have more car tunnels, then you would alleviate the congestion completely ... and you wouldn't need a flying car in that case, and it would always work, even if the weather is bad.

It would never ice up, and it would not fall on your head.

As chairman and CEO of Tesla Motors, which makes fancy electric cars that have just recently been upgraded to have some autopilot capabilities, Musk clearly has a stake in these innovations. As guest comedian Chuck Nice said on StarTalk, "those sound like the words of a man who owns a non-flying car company."

As Tyson said introducing the segment, "I really want a flying car ... But Elon cured me of my urges to fly in a flying car."

Listen to the entire episode of StarTalk, also featuring Bill Nye the Science Guy and comedian Nice, here: