The flying warehouse patent that Amazon recently announced is pie in the sky. Nor does much progress appear to being made toward drone deliveries. But the news that Amazon plans to build its first air cargo hub at Cincinnati/Northern Kentucky Airport is based on sound economics. When the 2-million-square-foot facility opens, it will reduce the company’s dependence on UPS and FedEx. But Amazon was already moving away from reliance on the parcel giants by giving an increasing share of its parcel business to lower cost regional providers. And many e-commerce shoppers have seen their orders delivered by the company’s fleet of private trucks.