Uber air taxi model is how you will largely see them first. Where I live the plan is to put them on top of a parking garage. You go there and they take you to the airport or downtown in which case regular car will take you the rest of the way. Makes sense to me. Until the self driving cars come along, cities are increasingly going to be in grid lock (though I think the timeline on those is too aggressive in the op). Other than that probably just play things for the wealthy.