Many of the world's major airlines are responsible for emitting millions of tons of greenhouse gases into the atmosophere every year. In 2023, American Airlines' operational scope 1 and scope 2 emissions totaled almost 38 million metric tons of carbon dioxide equivalent (MtCO₂e), only slightly more than United Airlines and Delta Airlines. These three airlines are among the largest airlines in the world based on revenue. In total, these 12 airlines produced more than 300 MtCO₂e in 2023.