Uber Technologies on Wednesday re-opened a contest to select the first international city to launch its proposed flying taxi project called UberAIR.

The service will be known, aims to launch demonstrator flights starting in 2020 and begin paid, intra-city operations in 2023, the company said.

Last year, Uber named Dallas and Los Angeles as its first launch cities and is now looking for a third,, Chief Product Officer Jeff Holden announced at its annual Elevate Summit in Los Angeles.

The company said it will consider cities with a metropolitan population of greater than 2 million people, with dispersed population hubs, an airport at least an hour away from the city center and which is willing to back pooled ridesharing services.

According to Uber, customers will be able order up air taxis via smartphone much the way the company has popularized ground-based taxi alternatives since it first launched in 2011.

The electric jet-powered vehicles look like a drone mixed with a fixed-wing aircraft. It will be able of both vertical take off and landing and rapid horizontal flight.