The White House on Wednesday said it was preparing the way for international rules to regulate commercial aviation emissions.
Moves by the Environmental Protection Agency (EPA) to link aircraft engines with climate change were the start of "an effort to lay the groundwork for a broader international agreement," spokesman Josh Earnest said.
"Obviously, these airplanes operate in a variety of different countries in many cases," Earnest said, pointing to the need for global rules under the International Civil Aviation Organization.
The EPA earlier stated that greenhouse gases from aircraft engines contributed to air pollution, climate change and endangered public health and should be regulated under the Clean Air Act.
The White House said "small piston engine planes and military aircraft would be exempted from these rules."
