On its website, Uber said that a good launch city has a population of over 2 million with a density of over 2,000 people per square mile, because those are the places that would benefit from an air taxi network the most. That's why that list includes some of the biggest and densest metropolitan areas in the world. Ideally, it will also have a large airport located an hour away that will make flying taxis a good choice of transportation for travelers.

According to The Verge, Uber decided on the five final choices due to what they can offer the company during the test period. India has congested cities, for instance, while Tokyo is humongous and Narita Airport is miles away from the center of the city. Paris, of course, is where Uber is building its flying taxi technology center.

Uber plans to announce its final choice in six months and to deploy its flying taxis there within five years. It's hoping the tests it conducts in those three cities can gather the data it needs to be able to expand to more locations and to make Vertical Take-Off and Landing (VTOL) aerial vehicles a common means of transportation.