As demand for air travel has declined due to the COVID-19 pandemic, one Canadian airline has offloaded a few of its planes to help Amazon.com Inc. move cargo.

Amazon announced Tuesday that the e-commerce giant purchased 11 Boeing 767-300 planes to add to its growing cargo fleet, including four from WestJet Airlines Ltd.

The online retailer said in a statement that the four planes from WestJet are currently being converted from passenger to cargo functionality and will join Amazon Air’s fleet later this year.

A WestJet spokesperson said the 767s were taken out of commission in 2020 as the company sought a buyer for the planes. A representative from Amazon confirmed via email that the WestJet planes were purchased in March.

“The Boeing 767 aircraft played an important initial role in setting up our transatlantic success and provided WestJet with critical widebody experience and an early understanding of the European market in order to successfully introduce our Boeing 787 Dreamliners,” a WestJet spokesperson said in an email. “We are pleased they found a home with Amazon.”

The other seven planes in the deal were acquired from Delta Air Lines Inc., Amazon said. ​