Why do people get the silly idea of flying cars?

Why make a future car that flys if we already have too many roads.What are are we gonna do ? Destroy our roads and make them obsolete in the future? You know you can't have land vehicles and flying ones at the same time.It would be chaos.We have enough with accidents on the road.Back to the future made it seem easy.It just doesn't work that way.Don't forget it would be very expensive to destroy our roads.