In addition to the excellent reasons you cite in your article, Abdul, the main reason we don't need - and will never get - flying cars is because they are a non-solution to the primary problem. We humans are, alas, absolute rubbish at problem-solving. We consistently make the error of seeing solutions framed purely as extensions of whatever it is we happen to be doing today. As you note at the beginning of your article, the nominal problem is traffic congestion. But the solution isn't dangerous and expensive and polluting flying cars: the solution is to shift assumptions.
The office was the late 18th century's answer to the need for centralized data processing in an age where paper and pen were what passed for hi-tech tools. As we've all just discovered (belatedly...) we don''t actually need to go into the office every day for most whitecollar jobs. Hence, congestion vanishes and likewise pollution & cost are massively reduced. Who needs flying cars if we're working from home? Reframing a problem is usually the best way to identify the optimal solution; it's a shame our brains are consistently terrible at this basic task.