"It could drop a hubcap and guillotine you."
If you could attach one name to the future of transport technology - whether it's self-driving cars, or spacecraft that can ferry humans to Mars - Elon Musk would have to be it.
So you might expect him to be all in on flying cars, but perhaps Musk is the voice of reason we all need when he says, "If somebody doesn't maintain their flying car, it could drop a hubcap and guillotine you."
In a recent interview with Max Chafkin at Bloomberg, the billionaire visionary says if we're going to be real about the possibility of flying cars, we have to imagine what a floating highway would actually feel like for those of us on the ground.
Let's face it - traffic is stressful enough as it is, but imagine a future where our skies are filled with giant metal boxes whirring ominously above our heads.
"Your anxiety level will not decrease as a result of things that weigh a lot buzzing around your head," says Musk.
And it might not even be that long before some of us get to experience it first-hand, with Dubai announcing earlier this week that they plan to launch the world's first flying taxi fleet by July.
"Passengers don't need to learn how to fly it, they don't need get to a pilot's license," Derrick Xiong from drone manufacturer EHang, which will be supplying the taxis, told Forbes last year.
"They just need to press a button and then it vertically takes off, flies from point A to point B, and lands."
By all accounts, it seems like Dubai is serious about this, and if they do actually get their flying taxis up and running this year, it will be a pretty great proof-of-concept for other cities to see how it fares.
But having a few rich people doing a 30-minute novelty ride a couple of times a day isn't exactly the Jetsons fantasy.
And Musk says that's kind of the point - he's out on flying cars because even a manned mission to Mars, a planet 54.6 million km (33.9 million miles) away at its closest, is a far more feasible moonshot.
As an engineer, he says the biggest problem he sees with flying cars is that big old bugbear - gravity.
"As long as the laws of physics hold, he explains, any flying car will need to generate a lot of downward force to stop it from falling out of the sky, which means wind and noise for those on the ground, not to mention debris from midair fender-benders," Max Chafkin writes for Bloomberg.
"Obviously, I like flying things," Musk told him. "But it's difficult to imagine the flying car becoming a scalable solution."
Instead of looking to the sky, Musk has opted to go underground, and earlier this month, we got to see the first section of the giant underground tunnel he's started building in the SpaceX parking lot in LA.
According to Business Insider, his new business venture, the Boring Company, has technology that can speed up the tunnelling process almost tenfold when compared to conventional methods.
While his plan relies heavily on getting permits to move his tunnel from beneath his own property to under public and private land elsewhere, Musk is confident that this tunnel will become something grand, and promises that it will at least accomodate cars - if not the speed-of-sound Hyperloop.
Granted, the prospect of driving through dark, underground tunnels isn't nearly as romantic as speeding among the skyscrapers, but Musk says we've already spread humans up and out - it's time to make our settlement of Earth "three-dimensional", he tells Chafkin:
"We have skyscrapers with all these levels, and we have a flat, two-dimensional road system. When everyone decides to go into these structures and then exits them at the same time, you're going to get jammed."
The one big safety issue that immediately comes to mind when you start considering vast networks of interconnected, car-sized tunnels is destabilising the surface.
But Musk isn't too worried about that, telling Bloomberg the mining industry has been boring holes into the Earth for centuries, and we still have a whole lot more Earth to burrow into.
"Earth is big, and we are small," he says. "We are so f*cking small you cannot believe it."
Flying versus tunnelling: let the games begin.
But if we had to put our money on one of those fantasies, we'll take the gloomy underground over hubcap decapitation any day.