Here's what I think is more likely: A small regional airport is taken over by Amazon. They build hangars and warehouses onsite. It's ramped up to land and fly a big turbine-powered mothership every five minutes. The warehouse dispatches packages to stacks of delivery drones like the one pictured in the video. The mothership loads the delivery drones in order. The motherships take off regularly, and then as the mother…
If you notice, both video examples show the drone delivering at a house. It seems obvious that an urban setting is difficult to address. And actually delivery costs are higher in the suburbs, due to population spread, than in the cities.
The interesting thing is how do UPS/FedEx/USPS feel about this, considering that Amazon is aiming to "evolve" their business model? We should soon hear about FedEx/UPS trying to do drone delivery. But this is not only logistics but also a lot of other software and I think Amazon might be better suited for it.