On Flying Cars

A journalist asked my opinion about flying cars. I wrote this.  Please tell me where I’m wrong.

For every technology pitch, you must ask not just “what is this like from the inside?” but also “what is it like from the outside?”  All vehicle technologies are sold based on how cool or useful it will be to ride them.  And most of these pitches do not want you think about what it will be like to be outside of them, or to share a city with them.

The issues with air taxis are obvious.  Even if they are much quieter than helicopters, they will introduce a new type level of noise to the city, anywhere near where they takeoff and land.  Their presence overhead in any numbers will have physical and emotional effects on the population.  They will introduce entirely new kinds of accidents that make everyone fearful of the space above them.  And in the end, by allowing elites to opt out of the transportation problems that everybody else in the city is having, they will encourage elite disinterest in solving those problems.

They will be cool to ride, though.



22 Responses to On Flying Cars

  1. Joshua October 16, 2019 at 12:02 pm #

    Also, does it scale? If not, it probably doesn’t matter much.

    Which I think is a variant of a quote by yourself 😉😊

    • Ned Carlson October 16, 2019 at 3:57 pm #

      Scaling depends mostly on noise and adoption. In absolute terms theres a lot more airspace than roads, the question is if we build anything like enough helipads, which aren’t a tough thing to add to a parking lot, but have a big regulatory and bigger NIMBY factor.

  2. Peter L October 16, 2019 at 1:45 pm #

    People do so well with automobiles that move in 2D, I’m sure they’ll do great with those that move in 3D. What could go wrong?

    No, Elon’s dream won’t fix the problem.

    Not going to happen in the lifetime of anyone reading this, or maybe ever.

  3. Laurence Aurbach October 16, 2019 at 2:04 pm #

    Watch the air-taxi chase in the movie “The Fifth Element.” Then ask yourself, do I really want Korben Dallas (Bruce Willis) flying over my house?

  4. Ben G October 16, 2019 at 5:53 pm #

    It’s nothing new and it’s not really surprising, but I’m always fascinated (read: disappointed) that discussions of transportation technology tend to focus on things that are futuristic and “sexy”, like self-driving cars, flying cars, and bullet trains (particularly in the US for the latter) — when we already have plenty of old, proven technology that can 100% solve our transportation problems right now. Why does hardly anyone (in the US) want to go for the low hanging fruit, like making cities walkable and bikeable? It’s at least 2 orders of magnitude more bang for your buck than any other transportation improvement. In how many cities in the US can most residents easily (and safely) walk or bike to nearly everything they need in a given month? Job, education, healthcare, food, shopping, entertainment, etc within, say, 3 miles. Six major cities, maybe? Less than 10% of the population? It’s criminal. Yet people waste their time planning for self-driving and flying cars. Ugh. What’s that phrase — lipstick on a pig is still a pig?

  5. Henry Miller October 17, 2019 at 9:40 am #

    Flying cars are mostly useless for transport inside of of a metropolitan area (city and the suburbs). Even if we assume training (and/or automation) to operate a flying car safety, the geometrical problems with cars don’t get much better when going to 3d space from 2.

    Cars need to have 2 seconds following distance front to back (most people ignore this rule), and about 5 feet side to side, and 25 feet vertical (only a factor for bridges). Flying cars need much more space side to side, and front to back, and 500 feet vertical. This assumes a grid layout where each compass direction gets a different altitude and when you want to change direction you need to change altitude. Such rules will be required if everybody has a flying car. However in the limited airspace above a city there will be enough flying cars that we cannot use the minimums: congestion in the air is deadly so you need to ensure the average flying car is much farther apart so that there is safe room to pass or change altitude as required. For an average we need to assume that you are typically a mile from the nearest plane in your 2d altitude so that there is room to move between altitudes as needed, or pass slower planes. Above 10,000 feet you need special equipment for air supply (both for the human and the engine) so there isn’t room above most cities for as many airplanes as they have cars crowding the freeways.

    Now I’m not a pilot: the exact numbers above are subject to argument, but the problem is the same as long as we insist on reasonable numbers: there isn’t enough space above cities for flying cars to be used every day.

    Flying cars might be useful for getting to “uncle bills ranch” in some remote area for vacation. However at that point it is a better deal to rent a small plane which you can do from any airport: no hauling wings around when you are not flying.

  6. Morgan Wick October 17, 2019 at 8:16 pm #

    Hey, remember the Jetsons which predicted a clean, shiny, utopian future of sky-high buildings and flying cars, of which the Jetsons’ seemed to be the only ones in the sky? A longstanding fan theory, actually hinted at in ancillary material, holds that literally everything is in the sky because the ground is literally uninhabitable! Even the show itself seems to suggest the ground has been mostly abandoned to the homeless, destitute, and general underclass! Sleep tight, kids!

  7. Anonymous October 17, 2019 at 10:59 pm #

    Henry: The two second rule is based on human reaction times, computers have much better reaction times so when robocars work properly they’ll be able to follow each other much closer and with V2V communications will be able to coordinate with each other to allow course changes while driving (or flying) in close formation.

    Of course flying cars have other problems improved control systems aren’t going to solve.

    Ben:To most people a bicycle is one of the least desirable transportation options, behind both cars and buses, except for a handful of bicycle enthusiasts most cyclists in the world would rather be car drivers and even if they can’t afford a car would stop riding their bike if a usable bus service existed. Short of serious disincentives to driving and crappy public transport, bicycles are a niche mode and it’s going to be hard to change unless you’ve already got a serious bicycle culture.

    • Dave October 22, 2019 at 7:52 pm #

      And apparently the future won’t have have any terrorists capable of hacking into the computer systems controlling safe distances between cars, flying or not. Which is good because even a single hacked car can cause massive crashes if purposefully steered into traffic the wrong way.

  8. asdf2 October 17, 2019 at 11:08 pm #

    “And most of these pitches do not want you think about what it will be like to be outside of them, or to share a city with them.”

    One particularly obnoxious example of such a pitch is when automakers in the mid-2000’s started making cars with key-fob remotes, in which the default behavior was for the car to honk its horn each time the car is locked. The feature is designed, thinking only of the experience between the car and its owner. The premise is that the owner is too lazy to tug on the door handle, or even turn around a look in the direction of the car (to see its flashers) when hitting the lock button. Hence, honking the horn to act as signal to confirm to the owner that the car is locked.

    But, when everybody does it, the result is that everywhere the cars park, there’s going to be honking. It’s particularly insidious for residential parking. Each person arriving by car late at night now wakes up everybody else in the building when they lock their car. It’s gotten bad enough that I now actively avoid bedrooms that overlook a parking lot.

    Traditionally, people tend to associate excessive honking with road rage. But, these days, the vast majority of unnecessary honking happens in cars that don’t even have a driver inside.

    While electric-powered flying cars shouldn’t be as loud as car horns, they won’t be silent. Electric-powered drones make plenty of noise, themselves, and it is hard to imagine a flying car capable of lifting the weight of humans any quieter than that. And, unlike highway noise, which you can get away from by moving to a quieter street, flying-car noise will be impossible to escape. And, they’re dangerous. And, they don’t scale.

    The UberCopter service in NYC is a complete abomination, forcing everyone in the flight path between Manhattan and JFK to listen to a constant stream of helicopters overhead so that a few rich people can get to the airport without having to choose between sitting in traffic in their chauffeured SUV or mingling with the common folk on the subway. The fact that such a service is even allowed to operate over such a heavily populated area shows that something is wrong with the government.

  9. Rob October 18, 2019 at 8:47 am #

    Obviously private sector entrepreneurs focus on the benefits to potential customers (especially wealthy ones willing to pay high margins). But in a tech world that leans heavily against government regulation and that values disruption as a positive (rather than a side effect), being blind to effects on others is almost baked in these days. I think it’s a given that the rich who increasingly prefer untouchable vertical neighborhoods in cities will insist on having an escape from the constraints of urban mobility that the rest of us have to suffer; I remember when I worked at Microsoft briefly in the 1980s there were already execs who helicoptered to work from their island homes.

    Jarrett, I think you’re right that our focus needs to be on the externalities and on urban livability and mobility for the rest of us. I think this is true whether we’re talking about flying cars carrying people, or drones delivering packages. And the same should be true for disruptive motorized wheeled thingies – we need to figure out how to make sure they don’t turn sidewalks and bike lanes into a battlefield. But the barrier to getting there now is a pro-disruption, anti-regulation libertarianism that seems to be baked into tech culture, and into a lot of new urbanist thinking as well. There’s money to be made, and the disruptors have no time to waste.

  10. RossB October 19, 2019 at 9:58 am #

    It is a silly question. The journalist obviously doesn’t understand the value of flying cars. First of all, very few Americans know how to fly an airplane. More play ultimate disc, or even lacrosse. Of those that do know how to fly a plane, my guess is a high percentage live in very remote areas (of Alaska, in particular). You just aren’t going to have a lot of people flying around town, because very few people know how to do it.

    Second, they don’t understand flying. Every flight involves a flight plan. You don’t just take off, willy-nilly, the way you do while driving. The reporter also doesn’t understand the value that is added here. It is not that people will suddenly take off from I-5, and land in a parking lot at work. That won’t happen — it isn’t legal.

    The value is in storage. If you talk to someone who owns an airplane, in an urban or suburban environment, this is a big deal. It isn’t a lot different than boating. If you own a big boat, it costs a lot of money to store it in the water if you live in the city. But some people own a big truck, and a big trailer, and just store it in their backyard. You can’t do that with an airplane — yet. But if you could, there would be lots of people who would be interested. That is the market for the flying car. It would be expensive (like a trailer and a big truck) but still cheaper in the long run than paying for hangar space.

    Asking someone like Jarrett Walker about the subject might elicit an interesting response (and it did) but it has little to do with public transportation. You might as well ask him what he thinks of the Blazers this year or what fresh hop beer to recommend.

    • Transit Riding Transit Planner October 22, 2019 at 3:36 pm #

      The problem is that you do actually have influential people, including Board members of agencies that control transportation funding, who think that flying cars are relevant to the general conversation about transportation. We have Board members of my MPO saying things like “We should be talking more about flying cars,” with the implied extension of that sentence being, “… and less time talking about all this humdrum 20th century stuff like buses, trains, and highways.” That’s why it’s relevant to people like Jarrett. We transportation planners need to be able to cogently explain why this will NOT resolve any major problems in transportation planning in the foreseeable future.

  11. Anonymous October 19, 2019 at 9:04 pm #

    RossB: There are aircraft with wings that detach or fold back allowing an aircraft to be put on a trailer and towed from the airport to home.

    The biggest commonality with boating though is that it’s mostly done for fun.

    • RossB October 22, 2019 at 7:42 am #

      “There are aircraft with wings that detach or fold back allowing an aircraft to be put on a trailer and towed from the airport to home.”

      Yep, same sort of thing. This is a variation on a theme — the ability to store an aircraft at home. It is not about driving down the freeway and landing at a parking lot at work.

  12. Warren October 21, 2019 at 11:54 am #

    Obviously the answer here is to let Elon build his tunnels and relegate the flying cars to only using the tunnels.

  13. Omri Shaffer October 22, 2019 at 7:22 am #

    Great post

  14. Magellan October 22, 2019 at 7:54 am #

    Interesting debate. I believe EVTOLs will replace helicopters mainly because of their ability to reduce noise, environmental pollution and maintenance costs. And it is obvious that there will be specific rules and corridors to discipline traffic.
    I understand that the challenges are many, but in many places they will be overcome and become a cheaper and safer travel option than by car. Let’s wait.

  15. Anonymous October 23, 2019 at 1:51 am #

    Magellan: For low speed (up to and a bit beyond about 300 km/h) VTOL helicopters are probably about as efficient as you’ll get, if you don’t need much range switching to electric propulsion could work and having lots of rotors would also eliminate the single point of failure that is the gearbox so might even be worth doing if you’re going to power it by gas turbines (jet fuel still has much better energy density than any battery) and tail rotors are also one of the worst parts of most helicopters (uses energy but provides no lift, noisy, good at chopping up people who aren’t looking where they’re walking).

    The physics of VTOL is that you need to push air (or some other reaction mass) down, the larger the rotor area the lower the more air you push down so the lower the velocity you have to push it and how fast the air is moving tends to determine how much noise there is, those VTOL flying car proposals are likely to end up making more noise than a helicopter and the main environmental impact of helicopters is the noise.

    Warren: Now that is funny.

  16. Mark Bahner November 5, 2019 at 8:16 pm #

    I don’t think “flying cars” will ever happen, largely for the reasons you cite (but including energy efficiency and air pollution emissions…specifically particulate matter emissions).

    But what I *do* think will happen in a very big way will be parking lots of suburban retail stores converted into airports for autonomous vertical takeoff and landing (VTOL) aircraft. The parking lots (and the retail stores themselves) will be rendered obsolete by autonomous automobiles.

    Imagine an “airport” that is just an abandoned retail store for a “terminal” and a parking lot for airplanes to take off and land. Every town of more than say 50,000 people would have one or more of these airports, which would connect people to other cities within a few hundred mile radius. The planes would be small (less than 20 passengers) and take people to other cities in perhaps a 500 mile radius at speeds exceeding 300 mph.

  17. Anthony November 6, 2019 at 5:38 pm #

    I think flying cars are a great idea, but I think over cities there will be some obvious design constraints. Driverless, automated – sure, that’s a no-brainer. Clearly having big heavy things drop out of the sky isn’t going to be tolerated in densely populated areas, so maybe some kind of network of routes where they can go, making sure there’s nothing underneath to crash into. Since these routes will take up a city’s most precious resource —space, maybe we can just build a road-like raised platform above which these driverless flying cars can fly over regular traffic and city life. It would not be good if the driverless flying cars departed from those designated platforms, say from a gust of wind or software glitch so maybe attaching the flying cars to a railway on the platform would ensure they stay “on track” as it were. Now this network of raised platforms still has to exist in the city of limited space, so single occupancy is out. Perhaps these driverless flying cars on railway tracks on raised platforms should carry a few hundred people each and pick up and drop off people at stations every few miles or so and every few minutes. Furthermore in the dense core of cities, space is at such a premium that even these raised platforms have nowhere to exist, so I propose in the centre, these driverless flying car “tracks” can transition to underground tunnels.

    I propose we call it “Skytrain”.

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