Reducing aircraft CO2 emissions: The role of U.S. federal, state, and local policies

In January 2021, the U.S. Environmental Protection Agency (EPA) finalized a domestic aircraft carbon dioxide (CO2) standard that closely follows the international standard adopted by the International Civil Aviation Organization (ICAO) in 2016. This standard will go into effect for all new aircraft delivered in 2028 and thereafter, and previous ICCT research demonstrated that the average aircraft delivered in 2019 would have already passed ICAO’s standard by 6%. After the U.S. standard was proposed in July 2020, public comments submitted by various stakeholder groups highlighted that it would not reduce greenhouse gas (GHG) emissions from aircraft and aircraft engines, and now 12 states and the District of Columbia—which our analysis shows represent half of U.S. passenger airline emissions—have initiated a legal challenge to EPA’s standard. States are preempted by the Clean Air Act from setting their own aircraft emissions standards, and this briefing evaluates the states’ claim that EPA should set stronger federal regulations on this matter.

The authors find that aircraft are a significant source of many states’ GHG emissions; passenger flights account for about 10% of CO2 emitted in New York and California, mainly because they are the two highest emitting states in terms of total passenger flight emissions, as illustrated in the figure below. Also discussed are specific state- and local-level policy instruments, including R&D funding for zero-emission aviation and differentiated landing fees based on aircraft fuel efficiency, that could help mitigate aircraft emissions.