Before Uber unveiled its grand plan to establish a network of on-demand flying cars, Ricarda Bennett had already catalogued the legal challenges that could thwart the ride-hailing company's ambitions.

“Noise and safety are the key issues,” Bennett said.

In 2016, Uber tapped Bennett, a lawyer and heliport consultant based in Thousand Oaks, California, to help produce a white paper about its ambitious plans, which were the centerpiece of the company's ” Uber Elevate” conference on flying car technology in Dallas this week.