The ride-hailing service published details of its "on demand aviation" ambitions previous year which it has called Uber Elevate.
Today, Holden said Uber is still looking to start testing flying taxi services by 2020, first Los Angeles, and then in the Dallas-Fort Worth area-both of which are home to worldwide airports.
Uber is already testing another emerging technology, self-driving cars, in various cities around the country.
NASA calls its programme Urban Air Mobility, while Uber calls the vehicles it envisions EVTOLs (or Electric Vertical TakeOff and Landing aircraft).
"By the time the Olympics come in 2028, we believe Los Angeles residents will be making heavy use of UberAIR, showcasing one of the most advanced urban transportation systems to the world, and because uberAIR is all-electric from day one, it will have a net positive impact on the environment". That will allow their flying cars to take off and land vertically.
"UberAir will be performing far more flights on a daily basis than it has ever been done before".
Holden said: "Doing this safely and efficiently is going to require a foundational change in airspace management technologies".
On Tuesday, Uber took a step toward resolving that by signing an agreement with the National Aeronautics and Space Administration to develop new traffic concepts that will enable safe and efficient operations of robotic flight systems, the company said.
According to the company, passengers will travel in as-yet unbuilt electric aircrafts capable of traveling at speeds up to 200 miles per hour.
Alex Comisar, Garcetti's press secretary, said discussions with the company operating the technology in the city are in the preliminary stages. In February, Bloomberg reported that two former NASA employees, Mark Moore and Tom Prevot, joined Uber to work on aircraft design and traffic management software.
To get a sense, Uber projects that trips from the Los Angeles airport to the Staples Center during rush hour will take less than 30 minutes - down from 1 hour 20 minutes by auto. "L.A.is the flawless testing ground for new technology, and I look forward to seeing it grow in the coming years", Garcetti said.