Advanced air mobility (A.A.M.) took a leap forward in July when Dubai opened the world’s first purpose-built eVTOL vertiport. Developed by Skyports Infrastructure with Dubai’s Roads and Transport Authority, the 33,400-square-foot facility includes a passenger terminal, flight operations, two takeoff-and-landing pads, and Joby’s Global Electric Aviation Charging System. Built to handle 170,000 passengers and 42,000 aircraft movements annually, it will welcome its first electric-air-taxi flights soon. Dubai’s big bet on A.A.M.’s future will soon include three other new vertiports across the city. But most industry executives believe the quickest route to launching eVTOL service is to upgrade today’s helicopter infrastructure with charging systems. Blade Air Mobility founder and C.E.O. Rob Wiesenthal views a select number of heliports as ready-made starting points, particularly in places with enough transportation “friction” to justify the cost: dense urban centers such as Manhattan and Los Angeles or resort regions like the South of France, where congested roads and difficult terrain make short air hops especially valuable...