This article is drawn from the Transport Weekly newsletter from GreenBiz, running Tuesdays.

Some cities, such as San Francisco, can feel overrun by Uber drivers. Around my neighborhood, it's not uncommon to see multiple Uber drivers double-parked and idling on a single block. But if the ride-hailing gorilla has its way, Uber drivers could some day drive (and idle) in the skies, too.

And that's no joke to the company. At Fortune's Brainstorm Tech conference Monday afternoon, Uber CEO Dara Khosrowshahi discussed Uber Elevate, the company's urban air transportation program, with a straight face, and explained that cities won't always be able to keep up with the demands of transportation "in two dimensions."

Uber wants to launch a demo version of its "UberAir" service using electric aircraft in 2020 (likely in three international cities) and see a commercialized version by 2023. That's in just five years. Uber already has spent considerable money on R&D for the program, and has been running an annual summit on building the ecosystem around urban aircraft.

This flying car trend is the same one driving the growing interest in scooter sharing networks, dockless bike acquisitions and transit apps.

The reason you also should take these ideas seriously is that this "flying car" trend is the same one driving the growing interest in scooter sharing networks, dockless bike acquisitions and transit apps. It's that cities are getting denser, and it's making less sense for city residents to own cars, or suburban commuters to drive them into urban cores. At the same time, electric vehicles (including aircraft) are becoming more affordable, thanks to the dropping costs of batteries to power them. 

Cheaper batteries and computing technology are also leading to other sci-fi-style transportation demonstrations. Today, a company called Coast Autonomous plans to demo a slow-moving, self-driving shuttle in Times Square in NYC, which will move passengers around the pedestrian walkway. Some think that the first commercialized self-driving vehicles actually will be used in these slower-moving (and lower-risk) scenarios.

Such "out-there" innovations show just how swiftly transportation and mobility are evolving. It's changing at a pace much more akin to the digital world, than the one that has been dictated by years of planning and building city infrastructure. As Uber's Khosrowshahi put it during the Fortune interview: "We haven't had real innovation around personal transportation in 30 years. This is the first time we're really seeing it."

Here's my 10-story reading list in mobility for the week:

• Alphabet's Wing drone delivery project has graduated into an actual company. And here's Wired's profile of the simple hook that could help Wing deliver everything from burritos to medicine (via X blog post and Wired).
• George Hotz is on a hacker crusade against the "scam" of self-driving cars (via The Verge).
• Would you pay close to $600 a month for an all-access app for mobility-as-a-service? The Finnish startup Whim hopes so (via Bloomberg).
• From the San Francisco Chronicle's David Baker: "California is cutting greenhouse gases, but not from cars. Can that change?" (via SF Chronicle).
• It gets even weirder: flying trains! Wait, what!? (via Bloomberg).
• In the latest edition of what crazy thing Elon Musk will say on Twitter, he calls one of the Thai cave rescuers a "pedo." "Erratic" is good description to start with (via Gizmodo).
• Uber and Lyft aren't big fans of price-comparison apps. The latest they could crush: Bellhop (via Wired).
• The weak link in Amazon Prime's global domination: humans.
• California is fighting climate change with trees (via The New York Times).
• Milwaukee vs. Bird is the latest regional controversy over rogue scooter-sharing services (via WISN).

If you're looking to learn more about electric personal aircraft, slow-moving autonomous shuttles and many other ideas that will tickle your transportation fancy, check out VERGE 18 in Oakland, California, in October. The summer rate (40 percent off the onsite rate) expires Friday.