Airplanes are a rapidly growing source of emission in the transportation sector. In 2018, aircraft were responsible for about 3% of all carbon dioxide emissions and nearly 9% of greenhouse gas emission from the transportation industry. Commercial air travel accounts for the majority of aircraft carbon dioxide emissions.

Between 1990 and 2018, carbon dioxide emissions from domestic commercial flights increased about 18 percent. Recent studies estimate that aircraft emissions will increase dramatically over the next 20 years. Furthermore, airplanes remain the largest source of carbon dioxide emission in   the transportation sector that is not yet subject to federal greenhouse gas regulations.

The aviation is part of an increasingly interconnected global aviation sector that accounts for more than 2% of global carbon dioxide emissions but is one of the fastest-growing sources. Between 1990 and 2010, global aircraft carbon dioxide emissions increased by about 40% between 2013 and 2018, global emissions increased by 26%. If global aviation were a country, it would rank as the 20th largest emitter of carbon dioxide, and aircraft emission account for 24% of all global aircraft emissions. Without the new policy, global aircraft emissions are projected to triple by 205