Greg Lindsay, World Policy Institute; co-author, “Aerotropolis”

It’s no secret that our cities are growing – fast. The World Health Organization reports that today more than 50 percent of the world’s population lives in our urban centers. By 2050, it will be 70 percent. As countries and cities globally consider their next stages of economic growth, more and more it seems that future may tied to one area in particular: Transportation. As our urban centers grow, how do we rethink what urban mobility means? What does the next age look like? Greg Lindsay is a senior fellow of the World Policy Institute and co-author of “Aerotropolis: The Way We’ll Live Next.”