Amazon announced on Tuesday that it will add 15 more cargo planes to its fleet, leased through GE Capital Aviation Services.

By 2021, Amazon will have 70 planes in its in-house air fleet.

"These new aircraft create additional capacity for Amazon Air, building on the investment in our Prime Free One-Day program," Dave Clark, Senior Vice President of Worldwide Operations at Amazon, said in a press release.

Wolfe Research; Andy Kiersz/Business Insider

It's yet another sign of Amazon's growing interest in completing its own deliveries.

Amazon's worldwide shipping costs have grown fifteenfold from 2009 to 2018.

The text above is a summary, you can read full article here.