Flying Cars? You'll See Lord Lucan Water-Skiing Behind The Flying Dutchman First.
Look, to get anything to fly you need lift. Lift. LIFT! L.I.F.T do you hear? To get lift you need an aerofoil. Where in the name of all the devils of Hades do you think you are going to weld two twenty foot wings on to your Renault Clio?
Not to mention that to get the aerofoils to work you need thrust. Yes, SAAB did used to make cars and aeroplanes. And furthermore it is true that the Viggen had a jet engine built by Volvo. However neither Volvo nor SAAB ever strapped an RM8 turbofan engine to any of their roadgoing vehicles for the simple reason that it would have been really stupid.
As you have pointed out you could indeed attach a rotor to it in the manner of a helicopter. There are however three flaws in this argument that you are overlooking. The first is that you would in fact have invented a road-going-mass-murder-by-decapitation machine. The second is that if you attach helicopter rotors to a car, you will have to attach tail rotors to counter the torque and aid dirigibility. The third is that having accomplished the second you will not so much have invented a flying car as created a helicopter.
As you have further pointed out you could indeed put four electric motors on each corner and have it go up like a quadcopter drone. For about ninety seconds. Then you will be introduced to the concept of acceleration under gravity. Briefly.
However I do have a simple, effective and relatively cheap solution for you if you want a flying car. Show me which one is yours, and I will build an enormous catapult around and beneath it.