Following news from earlier this month that FedEx was dumping Amazon from its air cargo service, Amazon this morning announced the expansion of its own air delivery network, Amazon Air. The retailer says it’s leasing an additional 15 Boeing 737-800 cargo aircraft from partner GE Capital Aviation Services (GECAS). These will join the five Boeing 737-800’s already leased from GECAS, announced earlier this year. The aircraft will fly out of more than 20 U.S. air gateways in the Amazon Air network.

In addition, Amazon says it will open more air facilities in 2019, including at Fort Worth Alliance Airport, Wilmington Air Park and Chicago Rockford International Airport. Meanwhile, the main Air Hub at the Cincinnati/Northern Kentucky International Airport will open in 2021.

“We’re delighted to support Amazon Air’s dedicated air network,” said Richard Greener, GECAS Cargo’s senior vice president, in a statement. “The capability of the 737-800 freighter will further Amazon’s ability to provide reliable and regional delivery to its customers for years to come.”

The Amazon Air network, then called Prime Air, was first launched in 2016, with the goal of speeding up Amazon’s e-commerce deliveries, particularly for its Prime members. But over the years, the competition with partners-slash-rivals like FedEx have heated up — and not only on air cargo, but also in newer areas like ground delivery robots and drones.

At the end of last year, Amazon announced more aircraft additions for Amazon Air, bumping the network from 40 planes to 50. Today, it says it’s on track to reach 70 planes by 2021, thanks to this new expansion.

The company also claims to have created thousands of U.S. jobs thanks to Amazon’s investment of millions into its air network.

“These new aircraft create additional capacity for Amazon Air, building on the investment in our Prime Free One-Day program,” said Dave Clark, senior vice president of Worldwide Operations at Amazon, in an announcement. “By 2021, Amazon Air will have a portfolio of 70 aircraft flying in our dedicated air network.”

These investments around delivery logistics come at a time when Amazon says it’s trying to speed up Prime from two days to just one. The news prompted Walmart to announce a next-day shipping service of its own. Target, meanwhile, recently launched an integrated same-day shipping service on its website, powered by its same-day service, Shipt.

Amazon responded by noting it already has more than 10 million items available for one-day shipping today — reminding rivals that it’s still leading the market on this front.

Amazon also took the time today to highlight other areas where it’s investing in supply chain initiatives, including its Delivery Service Partner program, which helps people (including Amazon employees) start their own Amazon delivery business; plus Amazon’s crowdsourced package delivery workforce, Flex; and its dedicated network of more than 10,000 trailers to increase Amazon’s own trucking capacity.

Though not mentioned, Amazon also just rolled out a new Amazon Flex app for iOS. Launched on the App Store on June 12, the app lets individuals sign-up and be vetted to become an Amazon Flex contractor right from their iPhone.