United Airlines became the first U.S. airline to publicly commit to reducing its greenhouse gas emissions (GHG) by 50% by 2050. In a press release issued on September 13, 2018, United Airlines explained that it would achieve that reduction by expanding its use of more sustainable biofuels and by relying on more fuel-efficient aircraft and implementing other operational changes to better conserve fuel. United Airlines' commitment to reduce GHG emissions by 50% by 2020 is consistent with reduction targets established by the International Air Transport Association in May 2018.
U.S. EPA has yet to regulate GHG emissions from aircraft in the United States, notwithstanding U.S. EPA’s July 25, 2016 endangerment finding for GHG emissions from aircraft and U.S. EPA’s Advanced Notice of Proposed Rulemaking contemplating adoption of the International Civil Aviation Organization’s (ICAO) aviation carbon emission design standards.
The decision by United Airlines is likely to be followed by other U.S. carriers that have international routes because those carriers will be subject to the ICAO standards when flying internationally.