Flying Cars would be as safe as Helicopters and Planes are, once they get a viable technology mass produced, but I admit true "Delorean style" flying vehicles are not likely to appear in the next 40-50 years, except with very niche organizations (Police, airports, high end transportation?)
If there were as many private helicopters and planes as there are cars, helicopters and planes would not be safe anymore. Even with fancy antigravity technology. You simply can't have flying things in city streets. If things go wrong, you have cars crashing into the 50th floor of a building, or dropping straight on the ground on people from 200 meters.
Air traffic works the way it does because it is dominantly a public transport that takes place mostly outside the cities.