For the second time in as many years, Uber has gathered a thousand people in Los Angeles for the Elevate Summit, an event that “brings together 700+ of the world’s foremost on-demand aviation leaders in industry, government, and academia for 2 full days of programming.” Basically, it’s a circlejerk for people to talk in highly generic terms about flying cars that always seem to be “just three years away,” whether it’s 2001 or 2018.

At this year’s summit, Uber unveiled yet another flying car concept, this one being a four-passenger vertical-takeoff-and-landing (VTOL) fixed-wing aircraft, with vertical rotors fixed to those wings, giving an overall design that’s not dissimilar to the quadcopters that have become popular in recent years. While we got a good look at the luxurious interior, other minor details — how Uber will make batteries light enough for aircraft, train enough pilots, get approval to have hundreds of aircraft flying through cities, and design an entirely new air traffic control system — are still missing.

Uber envisages its air taxis picking up passengers at skyports on top of buildings or stations on the ground. The company wants the facilities to handle 200 takeoffs and landings per hour, giving a theoretical max of 800 passengers per hour per airport. The air taxis will then fly 1,000 to 2,000 feet off the ground, something Uber says will be possible thanks to the electric motors and multiple props, which make the aircraft quieter than a helicopter.

The company hopes to have pricing similar to an Uber Black on a per-mile basis, with cost eventually falling as low as UberX over the same distance. That might (emphasis on the might) be feasible one day, if all of Uber’s chips fall in the right place. If Uber can do away with the pilot and fly the vehicle autonomously, costs will be much lower. Electrification would also make the vehicle much cheaper to run and maintain, but that’s perhaps the biggest problem these vehicles have with becoming reality. Batteries with sufficient energy density to work don’t exist yet, and Uber asking for them to exist won’t help.