Such a big flying car would be big and heavy so need a lot of wing area, it means big and long wings to provide enough lift needed for flying. The wings aerodynamics lift center must be near the plane mass center, so wings must be not far from the middle of airplane body in practice. But how would we fold such a big wings that are in the middle of a car? I decided not to use one big wing, but make a biplane with the smaller wing span. Common biplane type is one wing above another, in this case they are more difficult to fold with its spatial structure, that's why I placed the wings in a tandem style. There are known biplane tandem airplanes that flies quite well, that makes the idea more realistic.
What benefits we have with the biplane tandem folding wings? We can gain a big wing area with relatively small wing span and wing width (so easier to fold). If it would be managed to achieve big wing area, then start and landing would perform with the slower velocity and that could allow for short start and landing way. By controlling the wings lift coefficient by (for example) flaps it is possible to control the position of the center of aerodynamics lift force, so in some range the airplane weight balance, by the aerodynamics. Using the same mechanism it is also possible to control the pitch so by having two tandem wings no height rudder is needed. The construction style doesn't depend of this, how heavy version of the plane is. The bigger the fuselage is, the longer wings can be fold on it, so even the heavy version can still be able to fly and after conversion drive on public road as a bus. Having a two tandem wings on the top of the fuselage, allows to fold them above the vehicle, so no critical space on the fuselage sides is taken. The wings are relatively light construction, so where wings are folded on the top, there is no big vertical center mass movement. Through the all conversion process, so wings folding and unfolding, the wings are integrated with the rest of vehicle body. That's is a big advantage for automatic folding and unfolding process, without any personal engage or manual work. On the bottom we can have something like wheels for a car, or boat shape if we want the vehicle to swim. There is nothing that could affect the construction in this place, so this is very good situation to make optimal design for function. The amphibian style is possible there, so we could have something that can fly, drive and swim. The big advance of such a flying car, is that you don't have to hangar it at airfield, you can just fold the wings and drive to your garage or some parking. It can land on small airfields so saving a lot of airport charges costs.