Amazon's buying spree for used planes makes green pledge harder to keep

While flight shaming and the coronavirus pandemic have spurred airlines to hasten the retirement of their oldest, fuel-guzzling aircraft, not all those planes end up in boneyards in the desert. Many find a second life in the fleets of Amazon.com Inc. and other cargo carriers.

Amazon has been among the biggest lessors of converted Boeing Co. 767s in the last five years as demand for online shopping has soared—more so since Covid-19 struck. A limited choice of converted planes and efforts to cap costs have left the online retailer with some of the freight sector’s oldest aircraft, many of them