You get a flying car factory (RAR!)

[Broomstick]

I think part of the solution here is to hire some very skilled lawyers to set up a waiver system in advance.

Oh, I'm with you on that one, but really, the situation is ridiculous.

For example, the manual to the Robinson 22 helicopter has a section where it states, in large, bold, bright red print IF YOU DO [particular maneuver] YOU WILL DIE. (Yes, I have actually read a manual for the R-22.) Nonetheless, whenever someone has attempted just that, invariably proving the manual to be absolutely correct, the heirs try to sue Robinson for making an unsafe helicopter.

By all means, make an iron-clad waiver - the world could use one.

Air traffic control "routes planes" all the time in real life, but does not take over the instruments and controls in the cockpit of those planes.

You would be surprised how many people out there really do think ATC has some sort of remote control power over aircraft.

Also, question: is life threatening turbulence likely to occur in unpredictable parts of the sky?

Yes, it can

I mean, we can predict that aircars shouldn't fly anywhere near a major storm system, where we can expect major updrafts/downdrafts/whatever that would swat them out of the air. That's easy to do automatically. Is it normal for there to be turbulence in basically clear air, that cannot be logically deduced from the ground, but is nevertheless intense enough to pose a deadly hazard to light aircraft?

It can be a deadly hazard to large aircraft. Yes, there is even a term for it: "clear air turbulence". Over North America it's mostly likely to occur on routes passing over the Rocky Mountains, and over mountain ranges world wide, but I'm pretty certain that theoretically it could happen nearly anywhere. You just need the right conditions.

Of course, CAT comes along a spectrum, from unexpected "bump" to harsh enough that when it swats a B-747 anyone not buckled in risks a quick trip to the ceiling and a broken neck (and yes, unsecured passenger have been killed in just that manner). As we come to understand more about it and thus are better able to predict where/when it is most likely to occur, less common than it used to be but severe turbulence is no joke.

Then there's the "normal" turbulence that comes with thunderstorms - the average person is clueless as to how far out the winds from those affect air travel. Add in icing effects and other fun and you can find a situation where even the largest and most powerful aircraft are under threat. This doesn't happen as often as it used to because, as I said, we know more and airplanes are routinely routed around rather than through storms (though Air France 447 was an exception... which demonstrated why flying through major thunderstorms is a Bad Idea even if you are a big jet).

If you seldom hear about fatal turbulence accidents it's because the vast majority of pilots respect that level of turbulence and stay the hell away from it. Stop and think - if the air is strong enough to hold up something weighing tons it is strong enough to exert a force of many tons on an object. Imagine your car getting bitch-slapped by something strong enough to hold up a B-7something7 or a large Airbus. That's what severe turbulence is. It's something that can fling 400,000 kg of airplane around the sky like a crumpled up ball of paper. That's why you don't want to fly too close to mountain tops, through major storm systems, and if you get a report of CAT you stay the hell out of that airspace.

But just imagine the average idiot bitching because the autopilot won't take him directly forward - "WTF? I can't see anything wrong!" Well, no, you can't see CAT.

[Simon_Jester]

Did the suits regarding the Robinson helicopter succeed? You can't stop people from suing as a rule, at best you just stop them from winning.

I think I always proceeded on the assumption you would need a pilot's license or a slightly-reduced form of one to use one of these, so yeah, the training is gonna be heavy on "Autopilot may be routing you around INVISIBLE DEATH, do not override unless you know it is malfunctioning and are in contact with a ground controller of some kind."

[Broomstick]

Did the suits regarding the Robinson helicopter succeed? You can't stop people from suing as a rule, at best you just stop them from winning.

I don't really have the time to dig up the details from the late 70's/early 80's but since this was pre-GARA I'm assuming there were some wins simply because Aircraft=Ooo, Scary to juries and a fair number of judges. The legacy liability wasn't as bad for Robinson as for some of the others simply because Robinson hadn't been around as long and didn't have tens of thousands of aircraft out there as potential liability but it was still a concern.

I think I always proceeded on the assumption you would need a pilot's license or a slightly-reduced form of one to use one of these, so yeah, the training is gonna be heavy on "Autopilot may be routing you around INVISIBLE DEATH, do not override unless you know it is malfunctioning and are in contact with a ground controller of some kind."

I suspect we'll also continue with our current airspace categories. If you're out flying over Kansas farmfields you might not have an autopilot requirement. If you're over New York City, LA, Chicago, Atlanta, etc. you'll be under stringent controls of some sort. Urban areas might restrict them to flying paths that follow existing roads to reduce noise and for safety reasons.

[Sky Captain]

If those aircars have no wings (they really don't need them since lift is generated by anti gravity unit) there would be much less total surface area than light aircraft of similar size and mass. That means they should be less affected by turbulence because there is less area for wind to catch. Light airplane that flies into serious turbulence can suffer broken wings and fall like a rock. Aircar that flies on anti gravity have no wings to break and anti gravity unit could also compensate for wind gusts. For example when encountering a strong downdraft autopilot increases the lifting power to remain at correct altitude and reduce the lift power if there is updraft.
Obviously flying into strong thunderstorms would be bad idea anyway, but if you can make those aircars robust enough to resist common turbulence that occour on normal windy days then you should be good to go. Othervise they would be dangerous to fly because during windy days tall buildings can also generate strong turbulence and aircars would often take off and land at close proximity to buildings if they are to replace cars.

[Broomstick]

If those aircars have no wings (they really don't need them since lift is generated by anti gravity unit) there would be much less total surface area than light aircraft of similar size and mass. That means they should be less affected by turbulence because there is less area for wind to catch.

Irrelevant. Turbulence is NOT like a wind battering a vehicle on the ground, turbulence is the air itself moving around. Again, it's as if the road bed is moving up and down, not the car moving in relation to the roadbed. It's not an object in a medium moving, it's the medium the object is embedded in moving.

What affects the reaction to turbulence is mass, not surface area. A larger mass has larger inertia and a larger mass resists sudden changes in motion better than a low mass. The aircars are on the low end of mass/weight, therefore, they're going to be affected like other small aircraft.

Aircar that flies on anti gravity have no wings to break and anti gravity unit could also compensate for wind gusts. For example when encountering a strong downdraft autopilot increases the lifting power to remain at correct altitude and reduce the lift power if there is updraft.

That depends on how quickly the anti-grav unit can compensate for sudden changes. Ordinary, most-likely-to-encounter turbulence, sure, but get caught in a micro-burst or mountain wave and there a difference of order of magnitude in acceleration.

Othervise they would be dangerous to fly because during windy days tall buildings can also generate strong turbulence and aircars would often take off and land at close proximity to buildings if they are to replace cars.

Yes, that IS a problem with tall buildings and one reason for the current minimum-distance regulations in regards to them.

[phongn]

Current state of the art in an automatic car can drive, and on real roads rather than just controlled, carefully organized test tracks.

This does not translate into being flexible, all-weather, or capable of avoiding pedestrians without human supervision, or avoiding small but significant obstacles in the roads. Or responding appropriately to street signs and lane markers in a construction zone.

Google's software can currently handle pedestrians, obstacles, construction zone lane closures and a bunch of other things. Not quite sure about how it handles bad weather; it uses active LIDAR that rain probably will do bad things to.

The AP still has to be able to keep track of other air traffic somehow, either on it's own or having the information relayed.

Maybe we need some sort of AI that functions like birds in a flock - flocking birds and schooling fish don't have a central controller, it's all based on individuals following a few simple rules based on the actions of those nearest to them.

Shouldn't ADS-B give you positioning information, at least?

Regarding the state of AP development, didn't the Russian space shuttle run its (one and only) unmanned test flight completely under automation?

Yes. Those are fairly controlled circumstances, though. The US orbiter also did most of its flight through automation as well.

Readers two decades from now would be thiking, 'what a quaint 20th century viewpoint'. The trajectory for road cars is now pretty clearly automation to the point where a qualified driver does not need to be present; the concepts for robot cars are all 'relax in the back while the car drives itself'. Aviation will lag for the usual reasons - primarily extremely high certification costs - but automation of the entire flight to the point of just dialing in a destination is technically possible and will be implemented (it is already for certain drones).

OPBH and AACUS are pretty much doing that right now for test programs using more or less off-the-shelf helicopters. There's a follow-on project called ALIAS that seeks to do more.

[Formless]

I have a business proposal almost immediately that has nothing to do with flying cars per say, but with the technology that makes them go. Isn't it possible to make a heavy lifting vehicle using the basic idea of the truck, but suped-up until it could fly a rocket up high into the atmosphere? Then I could offer SpaceX a deal where we develop a joint space launch concept, with my company making the air stage vehicle and their company making the accompanying rocket to get spacecraft the rest of the way to orbit. This should cut down space launch costs enormously, and our companies profit from the radical shift in how space launches are handled.

This is assuming, of course, that for whatever reason I can't just fit the anti-gravity engines onto a spacecraft directly and Millennium Falcon things into orbit.

[Sky Captain]

Irrelevant. Turbulence is NOT like a wind battering a vehicle on the ground, turbulence is the air itself moving around. Again, it's as if the road bed is moving up and down, not the car moving in relation to the roadbed. It's not an object in a medium moving, it's the medium the object is embedded in moving.

What affects the reaction to turbulence is mass, not surface area. A larger mass has larger inertia and a larger mass resists sudden changes in motion better than a low mass. The aircars are on the low end of mass/weight, therefore, they're going to be affected like other small aircraft.

Interesting, I thought mass per unit of surface area has major role. For example a normal brick and brick sized piece of styrofoam. Both have similar surface area, but brick has much more mass per unit of surface area Throw both from tall building during stormy day and brick will be little affected by wind while styrofoam brick will fly who knows where. That is extreme example, but those aircars may have something like 2 or 3 times more mass per unit of surface area than similar airplane because they lack wing and tail surfaces.

That depends on how quickly the anti-grav unit can compensate for sudden changes. Ordinary, most-likely-to-encounter turbulence, sure, but get caught in a micro-burst or mountain wave and there a difference of order of magnitude in acceleration.

What kind of wind speeds can be expected in those conditions? Given the mass and surface area of aircar it should be possible to calculate acceleration caused and how much force would be required to counter that acceleration.

[Simon_Jester]

Google's software can currently handle pedestrians, obstacles, construction zone lane closures and a bunch of other things. Not quite sure about how it handles bad weather; it uses active LIDAR that rain probably will do bad things to.

One question is, how does it handle a combination of the above problems? Say, if it's raining in a construction zone, or if the pedestrian is wearing light-absorbing clothing? Or if there's a possibility of ice making the surface of the road behave differently than the software is programmed to expect?

Also, the thing about construction zones is that they're most challenging when you have to make a judgment call about where to make your turnoff, things like that. I'm not sure how the automated car could handle that without the ability to (at the very least) read signs.

[LaCroix]

Irrelevant. Turbulence is NOT like a wind battering a vehicle on the ground, turbulence is the air itself moving around. Again, it's as if the road bed is moving up and down, not the car moving in relation to the roadbed. It's not an object in a medium moving, it's the medium the object is embedded in moving.

What affects the reaction to turbulence is mass, not surface area. A larger mass has larger inertia and a larger mass resists sudden changes in motion better than a low mass. The aircars are on the low end of mass/weight, therefore, they're going to be affected like other small aircraft.

You are not entirely right, I think.
Their lift is created by interaction with the gravitational field, not the air itself - which doesn't move. So they aren't actually embedded in the air insomuch as the air is present within the field they are embedded in. Much like a car, which is actually moving on the road and through the air, that AGcar is moving across the gravitational field, and also through the air. Turbulence therefore only impacts it's flight ability as in - we have gusts of wind. They would behave less like an airplane and more like a car subjected to gales in a storm.

The only thing the turbulence would directly affect is their primary drive, which is a jet, so their speed would be a bit erratic. But in this regard, the AG vehicle has options that a aerodynamic-lift vehicle doesn't have. They can slow down and even stop if they need to, as they are not restricted to a minimum air speed (or airflow across lifting surface). Which is one of the mayor problems of flying in turbulent weather - it messes with your lift generation. You can always slow to a hover (for a given value of, since you are still tossed around by the gales to some extent) and then slowly reduce altitude, until you have a (probably rough) landing. Or a mild crash, if the turbulence is still as bad at ground level. That could even be an automated "Land NOW!" emergency routine, not unlike the parachute in UL planes.

Would it be bad to fly such an AGcar in a storm? Yes. But only 'a good bit worse than driving a car in a bad storm' bad, instead of 'airplane tossed around like a rubber ball' bad.

[Beowulf]

If those aircars have no wings (they really don't need them since lift is generated by anti gravity unit) there would be much less total surface area than light aircraft of similar size and mass. That means they should be less affected by turbulence because there is less area for wind to catch.

Irrelevant. Turbulence is NOT like a wind battering a vehicle on the ground, turbulence is the air itself moving around. Again, it's as if the road bed is moving up and down, not the car moving in relation to the roadbed. It's not an object in a medium moving, it's the medium the object is embedded in moving.

What affects the reaction to turbulence is mass, not surface area. A larger mass has larger inertia and a larger mass resists sudden changes in motion better than a low mass. The aircars are on the low end of mass/weight, therefore, they're going to be affected like other small aircraft.

My CDCs state felt turbulence is inversely proportional to wing loading. Both mass and surface area matter. Less surface area means that you have less area for the moving medium to move apply force, and so create turbulence effects. Since these work on anti-gravity, not dynamic lift, they shouldn't have any wing area. You just have what fuselage lift is provided, and you probably want to minimize that. I'd say the closest analog would be a blimp, but those are slow as hell and have a terrific amount of surface area, and so probably aren't actually any good.

[Broomstick]

Irrelevant. Turbulence is NOT like a wind battering a vehicle on the ground, turbulence is the air itself moving around. Again, it's as if the road bed is moving up and down, not the car moving in relation to the roadbed. It's not an object in a medium moving, it's the medium the object is embedded in moving.

What affects the reaction to turbulence is mass, not surface area. A larger mass has larger inertia and a larger mass resists sudden changes in motion better than a low mass. The aircars are on the low end of mass/weight, therefore, they're going to be affected like other small aircraft.

Interesting, I thought mass per unit of surface area has major role. For example a normal brick and brick sized piece of styrofoam. Both have similar surface area, but brick has much more mass per unit of surface area

A brick also has more mass over all, and is much denser. While surface area can have an effect it's minor unless you have some greatly exaggerated differences (a mass that's kite-shaped as opposed to a densely crumpled ball of ball of the same mass). Your comparison is flawed because of the mass and density difference between the two bricks.

And on preview Beowulf said it better

That depends on how quickly the anti-grav unit can compensate for sudden changes. Ordinary, most-likely-to-encounter turbulence, sure, but get caught in a micro-burst or mountain wave and there a difference of order of magnitude in acceleration.

What kind of wind speeds can be expected in those conditions? Given the mass and surface area of aircar it should be possible to calculate acceleration caused and how much force would be required to counter that acceleration.

Microbursts reach airspeeds of 270 kph or even higher. There have been airplane crashes caused when the downward force exerted on an airplane exceeds the available power to overcome it, including very large and powerful aircraft. If it happens too low to the ground the plane is basically smashed into the dirt.

A mountain wave is a rotating air mass on the lee side of a mountain. Accidents involving large aircraft are rare these days because pilots are taught how to avoid them, but in 1966 a mountain wave near Mt. Fuji caused the in flight breakup of a B-707. It can still happen, though - a B-747 lost an engine, as in, it completely removed the engine from the airplane, in 1993 in Alaska. Think of them as horizontal, long-lasting tornadoes remaining in one location.

There are other weird atmospheric effects that can cause problems, but those are the two I know most about (second hand, thankfully - wouldn't want to be in either one).

Now, small aircraft do have some advantages over the larger ones. in the case of microbursts, small aircraft are batted about but because they lack the inertia of large airplanes they can (as an example) resume climbing quickly after exiting a microburst where the momentum of a big jet means they keep traveling downward for a bit after exiting. In a mountain wave, or any rotor wind, the small the wingspan and fuselage length the less likely the aircraft will be subjected to air masses moving opposite directions which, as the 1966 Mt. Fuji accident shows, can tear an aircraft apart mid-air. That is one respect in which a wingless aircar would, in fact, have an advantage. Small aircraft can still be destroyed - several years ago in Lansing, Illinois a Cessna 150 Aerobat was "sucked" (so one witness described it) into a storm cloud and a short time later both the airplane and its occupants came down in pieces near the airport they were trying to reach for a landing. And by that I mean the wind forces involved ripped the limbs off the pilots inside besides tearing the airplane apart. Which, again, is why pilots try to stay the fuck away from thunderstorms. The thing is, on the ground people can still safely drive during such a storm. This causes much confusion among the non-flying public these days - "hey, I managed to drive to the airport, why isn't that A-380 taking me to Boston!"

The best solution would probably have the AI land the flying car and convert to ground travel under such adverse weather conditions. There will be a potential for colossal traffic jams if you had a large vertical stack of them but it beats cleaning up after a fatal accident.

[Broomstick]

You are not entirely right, I think.

Quite likely - wouldn't be the first time, either.

Their lift is created by interaction with the gravitational field, not the air itself - which doesn't move.

Actually, the wind DOES move, that's why we have turbulence. Yes, it probably will be different than aircraft dependent on lift, but it will still have an effect.

You would, of course, eliminate the problem of turbulence inducing or contributing to a stall which would eliminated one hazard.

That could even be an automated "Land NOW!" emergency routine, not unlike the parachute in UL planes.

Strictly speaking, those parachutes aren't automated, they're triggered by the occupant pulling a big-ass red handle in the cockpit, but yeah, emergency options are a good idea. Of course, each and every one of those parachutes has the warning that their use does not guarantee survival, they just increase your odds.

Really, a full-craft parachute for these is probably a good idea. They're well within the viable size range for those.

Would it be bad to fly such an AGcar in a storm? Yes. But only 'a good bit worse than driving a car in a bad storm' bad, instead of 'airplane tossed around like a rubber ball' bad.

The thing is, the higher off the ground you are the higher the wind speeds. You can also get rotating air masses which bear a more than passing resemblance to a tornado. Sure, sometimes a rotating air mass is not a big deal - a few years ago I posted an account of flying through a dust devil, which was entertaining and not frightening or dangerous - but it certainly can be.

[Sky Captain]

Microbursts reach airspeeds of 270 kph or even higher. There have been airplane crashes caused when the downward force exerted on an airplane exceeds the available power to overcome it, including very large and powerful aircraft. If it happens too low to the ground the plane is basically smashed into the dirt.

Well, according to this calculator

https://www.soundcedar.com/calculators/ ... late+Force

270 kph wind generate about 134 lbs of force per square foot or 635 kg per square meter on a flat structure. If our aircar is 4,5 m long and 2 m wide and fuselage is slab sided fairly unaerodynamic it would experience about 5700 kg of downwards force in a severe microburst. If anti gravity system can produce such upward force it should be fine even in severe weather conditions. Assuming fuselage is aerodynamically shaped the applied wind force and required lift power to compensate for it would be somewhat smaller.

[Sea Skimmer]

Course, it would in fact be highly aerodynamic, because why on earth wouldn't it be? Even if the cargo/passenger survival cell is rather box or sphere like in shape it'd have fairing on it for lower drag, and potentially the near elimination of reflected pressure from the top and bottom as well as dead ahead. Drag loading on a curved surface generally can't even get close to the reflected pressure loading on a flat surface, unless you start to hit compressibility limits, which is easily avoided in the design phase when we don't even need a wing. Microbursts are so dangerous because they don't just force the plane down, they also at least partly stall the wing in level flight. The later doesn't happen here. Out of hand they are much less of a threat, and in any case something that we can now fairly easily detect on radar, as well as conditions suitable for their formation. A shift to flying cars would also mean a shift in public safety spending, such as greater concentrations of high performance weather radars, instead of relying so much on NEXRAD sites providing minimal coverage at 3rpm. We'd build that instead of building more interchanges and installing traffic cameras ect.... though god help the people in charge of the ATC system at that point.

Even if the anti gravity system does not have a reserve of performance or an altitude-lift curve, the engine would almost certainly be designed for a wide range of thrust vectoring (makes way more sense at this point then control surfaces), and since loss of forward speed doesn't cause a crash you can potentially use all of it for maneuvering thrust. Bonus that since electrical power has been specified it will be much harder for the engine to stall, nearly impossible I should think except for massively intensive rainfall, and even when we get instant resumption of thrust once the rain intensity goes down.

[biostem]

I wonder if you could adapt the AGCar to basically be a "car with no wheel" - in other words, hard-wire it to only fly a few feet above the ground, and you now remove most of the wear and tear on the roads and vehicles themselves. Of course, the only standout issue is how well can the care brake or turn? Either way, by restricting the altitude for general use, you cut out a lot of potential issues. As others mentioned, some sort of advanced licensing system would/should be implemented for those that wish to operate said cars at higher altitudes.

[Beowulf]

I wonder if you could adapt the AGCar to basically be a "car with no wheel" - in other words, hard-wire it to only fly a few feet above the ground, and you now remove most of the wear and tear on the roads and vehicles themselves. Of course, the only standout issue is how well can the care brake or turn? Either way, by restricting the altitude for general use, you cut out a lot of potential issues. As others mentioned, some sort of advanced licensing system would/should be implemented for those that wish to operate said cars at higher altitudes.

You're probably going to end up with something that manuevers like a hover craft. Without traction, you're going to be thrown sideways a decent amount with any amount of gusting. Also, jet engines (even electric ones) are significantly worse in power efficiency than a drivetrain. You're better off just using the battery tech for a better electric car.

[biostem]

I wonder if you could adapt the AGCar to basically be a "car with no wheel" - in other words, hard-wire it to only fly a few feet above the ground, and you now remove most of the wear and tear on the roads and vehicles themselves. Of course, the only standout issue is how well can the care brake or turn? Either way, by restricting the altitude for general use, you cut out a lot of potential issues. As others mentioned, some sort of advanced licensing system would/should be implemented for those that wish to operate said cars at higher altitudes.

You're probably going to end up with something that manuevers like a hover craft. Without traction, you're going to be thrown sideways a decent amount with any amount of gusting. Also, jet engines (even electric ones) are significantly worse in power efficiency than a drivetrain. You're better off just using the battery tech for a better electric car.

You bring up some good points. I wonder if you could use the anti-grav tech to sort of reduce the weight of the car that the electric motor would have to carry, then - sort of a best of both worlds implementation - This would really help with preventing getting stuck in mud, or if you get a flat tire, just engage the AG unit so the car can levitate while you easily change the tire, or just hover home if that's not an option.

Heck, I'm sure there are some medical application, where being able to easily levitate someone would help with recovery as well...

[Broomstick]

Being able to levitate someone recovery from an injury or illness would really help with reducing bedsores. Might also help with some paralysis cases as well, not restoring movement but, again, reducing pressure sores and making them more mobile.

[biostem]

Being able to levitate someone recovery from an injury or illness would really help with reducing bedsores. Might also help with some paralysis cases as well, not restoring movement but, again, reducing pressure sores and making them more mobile.

I wonder if you could incorporate a small AG device into a belt or backpack, to aid in people with reduced strength/mobility or similar ailments.

[Sky Captain]

Also, jet engines (even electric ones) are significantly worse in power efficiency than a drivetrain.

How do you make an electric jet engine? Some sort of heating coil where combustion chamber is inside normal jet engine? Why not simply use ducted fan powered by electric motor and get away with a lot of complexities and maintenance issues involving jet engines. Modern high bypass ratio turbofans already get most of the thrust from the large fan, jet engine is mainly there to drive the fan. Put electric motor in place of jet engine and everything becomes simpler and also much less noise is produced. Electric motors as long as basic maintenance is performed are nearly fool proof.

You're probably going to end up with something that manuevers like a hover craft. Without traction, you're going to be thrown sideways a decent amount with any amount of gusting. Also, jet engines (even electric ones) are significantly worse in power efficiency than a drivetrain. You're better off just using the battery tech for a better electric car.

If you use anti gravity to operate like a hovercraft you still have to go at speed similar to normal wheeled car and have all the problems with traffic jams. Main advantage of a flying car is ability to go much faster than ground car and wast increase of available space given competent ATC system would practically eliminate traffic jams. 2 hours of stop and go driving in rush hour traffic to get to work place would turn into short 5 - 10 minute flight.

[Beowulf]

Fuck if I know how to make an electric jet. It's what's specified in the OP though. My point remains, in that something that levitates just above the surface, and is moved by moving air is pretty much the worst idea possible with the given technology.

[Sea Skimmer]

You just have some high power heating elements instead of fuel injectors and a really high pressure ratio. Its rather simple to do if indeed excessive, at that point even a motorjet would make more sense using only waste heat for expansion, before you even get to a mere ducted fan that is much more logical. It doesn't seem super important though how the things are propelled though for debate purposes, with no wing its not going to need very much thrust. With an idealized shape the drag will be incredibly low, and while acceleration might also be very low reaching the quoted top speeds might not be taking more then ~100lb kind of engine thrust. Low accleration will be okay if ATC is good enough to avoid constant stops, and of course you can have very effective air brakes given the low masses and lack of danger of stalling.

Flying cars wouldn't just eliminate traffic jams, they'd make it actually possible to start reclaiming roadspace and at the least halting further major expansion. Rail can take back a huge amount of freight if we don't super subsidize the roads and bridges anymore, and in many cases it wont even increase costs, or at least cost will be very limited. Such as companies needing higher inventories and thus more capital on hand, but the direct transport cost isn't higher. Some kind of depressing indications are many companies in the US are actually wasting money on trucking even with the system as it is, they just don't even consider rail and get prices.

[Simon_Jester]

You're probably going to end up with something that manuevers like a hover craft. Without traction, you're going to be thrown sideways a decent amount with any amount of gusting. Also, jet engines (even electric ones) are significantly worse in power efficiency than a drivetrain. You're better off just using the battery tech for a better electric car.

Reducing the gravitational mass of a car runs into some problems with handling.

One, the friction keeping the car on the road decreases; take it too far and the wheels start skidding instead of getting traction on the road surface.

Two, the car's inertial mass is unchanged, so it doesn't accelerate faster on a level surface. It does climb hills faster, but for freeway driving this isn't the main offender requiring the car to consume energy and fuel.

Three, the car becomes more susceptible to crosswinds and the like compared to a normal vehicle. Still not as bad as a hovercraft, but potentially bad enough to cause problems for drivers accustomed to normal vehicles.

Heck, I'm sure there are some medical application, where being able to easily levitate someone would help with recovery as well...

There are infinite applications, both to being able to levitate objects on a 'hover-support,' and (hopefully) being able to use the device to exert force on objects at a distance without touching them (tractor/pressor beams).

I wonder if you could incorporate a small AG device into a belt or backpack, to aid in people with reduced strength/mobility or similar ailments.

Like the suspensor-globes in Dune!

[Darmalus]

This talk of freight suddenly makes me think of attaching those lifters to container ships. Big enough to deal with turbulence (I hope), trained crews, and drop the cargo off on any convenient flat area. It's already the cheapest way to ship things as I recall.