For the first time, Amazon is calling itself a "transportation service provider," as seen in its annual 10-K filing.
The company makes the classification in the "cost of sales" portion of the report (emphasis ours):
Cost of sales primarily consists of the purchase price of consumer products, digital media content costs where we record revenue gross, including Prime Video and Prime Music, packaging supplies, sortation and delivery centers and related equipment costs, and inbound and outbound shipping costs, including where we are the transportation service provider.