Your comparison with Red Flag Laws, which were repealed before 1900 (yes, in the USA, but in the UK as well, I believe), is a silly red herring. Aircraft altitude minimums were established many decades ago, and if anything they’ve become more strict rather than less. Read the actual regs. Among them is one that requires staying within gliding range of a safe place to at least crash-land without harming bystanders. Since helicopters of whatever stripe get a considerably steeper glide than fixed-wing craft, that restriction typically means they should fly higher over populated areas. Of course rules can change, but give me a good reason for changing these. So that tens of thousands of unskilled air commuters can swarm the skies? Sorry, no. Not happening.

It’s not even close that I don’t believe something can happen until it does. I’m working on a major bioenergy project right now that is far from certain to come to fruition. But there’s a difference between optimism and believing in magic snake oil, which is what these Terrafuggia guys, and your quadcopter guys, are selling. If you want to follow your belief with investment money, go ahead. But when you come up empty-handed, don’t say you weren’t warned.

Serious people in the real aviation industry aren’t even fantasizing about electric aircraft in the foreseeable future. Liquid carbon-based fuels are the only real choice. If/when batteries become practical for flight, we’ll start seeing them in conventional aircraft, but that’s not even in the works. Gasoline still has about 13x the delivered work energy density of the best practical batteries.

I don’t dispute your calculations, but when you account for the batteries and two people including their briefcases and shoes, you’re only left with 130-140 kg of empty aircraft. Really? Sounds extremely optimistic.

Comparing electricity with bus fare is misleading at best. What about the cost of the aircraft? The simplest, most comparable light airplane, a Cessna 150, would sell for about $200k now if it were still in production. What reason is there to believe that a hightech aerocar or quadrotor would sell for less?

Self-driving cars notwithstanding, you’re in fantasyland with your autopilot system. For good reasons, the aviation world is careful and conservative about this kind of thing, and about pilot qualifications, even for arguably self-flying airliners. There are no slippery roads in the sky, but there is a little thing called weather, and good, experienced human judgement is still a necessity.

I don’t know which city you live in, but in the U.S. there’s a good reason you wouldn’t see air traffic below 100m: the legal minimum for ALL aircraft (quadcopters and aerocars not excepted) is 300m! Above the highest obstacle within 600m. At all times (see federal regulations excerpt below).

Most urban/suburban areas qualify as “congested” under these regs. Aside from any traffic implications, this means that you are NOT allowed to land in your or your neighbor’s driveway or lawn. Or in some convenient local parking lot. Period. Legal airports only. Of course there are exceptions for qualified helipads on many highrise buildings, but those are relatively few, and they’re not for the use of your imaginary everyday air commuter.

From U.S. federal regulations:
§ 91.119 Minimum safe altitudes: General.

Except when necessary for takeoff or landing, no person may operate an aircraft below the following altitudes:

(a) Anywhere. An altitude allowing, if a power unit fails, an emergency landing without undue hazard to persons or property on the surface.

(b) Over congested areas. Over any congested area of a city, town, or settlement, or over any open air assembly of persons, an altitude of 1,000 feet above the highest obstacle within a horizontal radius of 2,000 feet of the aircraft.

(c) Over other than congested areas. An altitude of 500 feet above the surface, except over open water or sparsely populated areas. In those cases, the aircraft may not be operated closer than 500 feet to any person, vessel, vehicle, or structure.

The weight they give is 450Kg, with 20 min flying time at present, with a max speed of 100kph. If we assume the 20 mins is at 70kph, thats a 23k range (further than many peoples trip to work in the morning)

Of the 450kg, say 150kg is battery, with an energy density of 160Wh/KG. Thats a 24KWh battery. Its about 1KWh per kilometer travelled, and thats for 2 people.

In my city it costs about $2.50 per person for a 10k bus trip to or from town.

The energy cost from rooftop solar at say 15c/KWh for 2 people would be 10KW*15c = $1.50 vs $5 for 2 people in the bus. Now thats a rough estimate, but the costs clearly aren’t prohibitive.

I think you are quite off the mark about air traffic. Making an autopilot system for such vehicles would be much easier than making a self-driving car and we already have self driving cars. There are no pedestrians, road works, slippery roads, or unpredictable drivers in the sky. Make every vehicle autopilot and fly at less than 100m high in areas where fixed wing aircraft don’t fly and there are no mixing issues. In the vast majority of my city there is no air traffic <100m at present. For the air traffic system, just make the copters follow the roads, but at 10m, 20m, 30m -100m intervals directly above them in the sky. You also don't need to have head on traffic. 10m can be northbound, 20 southbound, 30m east, 40m west etc. To change direction, you (autopilot) pull over, change altitude then pull into the appropriate lane again. Current radar can easily pick up a vehicle of that size 1-20 seconds ahead even in the thickest fog. You get into the copter, tell it your route, it accepts it then takes you there. So there is no landing in someone elses driveway, but flying from one parking space to another. It could land on your lawn quite happily too. Flying in already noisy rush hour when it is most needed I don't think is going to add to the noise pollution that much either. Multi rotor craft would be quieter than helicopters because each blade is not breaking the sound barrier unlike a helicopter.

Yes it may take more energy than a car on the ground, but if it removes that car from gridlock everyone else gets home a little faster. Until you know the mass production cost to make one, and the minimum energy to take 2 passengers 20k or so, then you can’t draw that conclusion.

What rubbish (sorry cleantechnica, you should do better!)

The comparison was made between a car (single occupant private vehicle) and common airflight, which is a form of public transport with 100’s sharing the same vehicle. To extrapolate that into the environmental impact of a single occupant flying vehicle is impossible and in fact misleading to the readers of CleanTechnica.

The second thing that this assertion totally ignores is the increase of VMT because of this much faster, congestion proof vehicle. So even if the energy use per km is the same, people suddenly find they can cover much larger distances in the same time. And they will take advantage of that, increasing the total amount of fossil fuels burnt.

The third thing that is ignored is that air flight is much harder to electrify than ground transport. So while cars will increasingly travel on electricity (from clean sources), this thing will need hydrocarbons for the foreseeable future. Guess where those hydrocarbons will have to come from? Think Canada, think Keystone XL.

Please do not go down the path of publishing this kind of stuff that has nothing to do with clean neither with technica.

Of course you wouldn’t want the completely unnecessary situation of individual ownership, the same copter could take multiple trips to and from work on the same day, greatly spreading the probably high cost to buy one around many ppl. Even if the richest 10% used it, thats still less traffic on the ground.