Technically there have been flying cars... not in the Jetsons mold of course but a few companies have tried to make them and have successfully pulled it off technology wise. The issue is that a vehicle that does both is pretty damn terrible at flying relative to planes and at driving relative to cars. There are tons of other issues with it too, i.e. any minor fender bender as a "car" grounds it as a plane, and pilot training requirements, etc. It's an interesting concept but one I don't think will ever be widespread like a lot of media has depicted.
"Flying car" == small, cheap, self piloting helicopter.
The "cheap" part is the big problem. The "self piloting" part is, in many ways, simpler than self-driving cars because there are so few obstacles in comparison, but failures are much more likely to be fatal.
It only takes one company to get this idea "off the ground" though, and the barriers are price, space, and regulatory requirements. The charter helicopter business in Manhattan is booming, but only because there are enough helipads and high end customers. Get the cost down to $100 a ride instead of $1000 and allow urban takeoff/landing from a much wider variety of locations, and suddenly a whole new business model appears -- and then some municipality becomes the testbed by handwaving the regulatory environment away.
This kind of transformation isn't imminent, until it is. Just like, say, chatgpt. The foundations don't exist, until one day they do.