Amazon.com Inc. said on Wednesday it leased 12 Boeing 767-300 converted cargo aircraft from Air Transport Services Group Inc., bringing its total fleet to more than 80, as it pushes for faster delivery to meet a surge in online orders.

One of the new aircraft joined the online retailer's operations in May while the remaining 11 will be delivered in 2021, the company said in a statement.

Amazon is also opening regional hubs to support its growing air network. This summer it will open new regional air hubs at Lakeland Linder International Airport in Florida.

Amazon is building a delivery network to service its own business and potentially rival those of major carriers such as FedEx Corp., United Parcel Service Inc. and Deutsche Post DHL.

FedEx has the largest air cargo fleet of the big three delivery companies, with more than 650 aircraft.