I believe that with the economy of our world today, flying cars will be too costly and it will completely change our planet and people will have to try to adapt to the new environment, instead if you just further advance road cars then you wont have to change the rules of the road and you will be able to continue with the skills or driving that you are already known for. Flying cars would have many problems being first generation vehicles while road cars would keep advancing their technology.
the company Terrafugia has already designed flying cars and made prototypes. I believe flying cars are going to be a major source of transportation in the next 25 years. Flying cars will help to avoid traffic and will assist in getting to the destination in a timely matter. These abilities will allow people to get more done. When people get more done, we become more efficient as a nation. When we become more efficient as a nation, we grow.