The problem is that the limitation is physics, not engineering. There is little overlap between what characteristics make a good airplane and what make a good car. Additionally, many of the characteristics that make a good [airplane|car] directly work against your efforts to make a good [car|airplane].
Let me give you some concrete examples: You want an airplane to be light, have good impact protection from the front (because airplanes very rarely get run into by a mountain from behind), and not require long runways. A car, on the other hand, must have good impact protection from all sides, fit inside a lane on the road, and good acceleration so you can merge onto the freeway.
The second car requirement and last airplane requirement together necessitate folding wings, which are heavier than fixed wings (and also more complicated and more expensive). Short of a powered-lift design (which is going to be even more insanely expensive), there is no other way around the physics. It doesn't matter how good your engineers are. Physics puts limits on what you can do with a wing.
The side and rear impact protection on a car do nothing beneficial to the airplane, but add weight. Again, clever engineering can only do so much within the limits of physics with regard to material strength. I don't care if you use the most expensive quantum-dot-infused titanium-nanotubes: Real-world materials have strength limits.
As part of making an airplane light, you're probably going to want to put a small, air-cooled engine in it (the Rotax 912, used in the linked aircar, produces between about 90 and 110 HP, depending on the variant). Even a light car is going to have very poor acceleration with that engine. Again, this is a matter of physics: F=ma. Some sort of continuously-variable transmission will help a bit, but you still only have 110 HP to work with.
Smartphones have improved radically over the past 10 years because the problem was not physics, but rather engineering. Software engineers made better software (which is really what made the iPhone different from Blackberries when it was introduced) and hardware engineers made better CPUs to run the software at a decent speed.
Let me give you some concrete examples: You want an airplane to be light, have good impact protection from the front (because airplanes very rarely get run into by a mountain from behind), and not require long runways. A car, on the other hand, must have good impact protection from all sides, fit inside a lane on the road, and good acceleration so you can merge onto the freeway.
The second car requirement and last airplane requirement together necessitate folding wings, which are heavier than fixed wings (and also more complicated and more expensive). Short of a powered-lift design (which is going to be even more insanely expensive), there is no other way around the physics. It doesn't matter how good your engineers are. Physics puts limits on what you can do with a wing.
The side and rear impact protection on a car do nothing beneficial to the airplane, but add weight. Again, clever engineering can only do so much within the limits of physics with regard to material strength. I don't care if you use the most expensive quantum-dot-infused titanium-nanotubes: Real-world materials have strength limits.
As part of making an airplane light, you're probably going to want to put a small, air-cooled engine in it (the Rotax 912, used in the linked aircar, produces between about 90 and 110 HP, depending on the variant). Even a light car is going to have very poor acceleration with that engine. Again, this is a matter of physics: F=ma. Some sort of continuously-variable transmission will help a bit, but you still only have 110 HP to work with.
Smartphones have improved radically over the past 10 years because the problem was not physics, but rather engineering. Software engineers made better software (which is really what made the iPhone different from Blackberries when it was introduced) and hardware engineers made better CPUs to run the software at a decent speed.