WASHINGTON - New Jersey, Pennsylvania and several other states, cities and environmental groups intend to file legal petitions today demanding that the federal government order a reduction of greenhouse gases emitted by aircraft.

Aircraft account for 3 percent of the United States' emissions of carbon dioxide, the main gas responsible for warming, the Environmental Protection Agency reported in April. U.S. carriers account for nearly half the carbon emissions from aircraft worldwide.

Aircraft also spew nitrogen oxides, gases that have more impact on global warming at the altitudes of air travel than they would at ground level.

The EPA has issued standards on some types of aircraft pollution but not greenhouse-gas emissions.

The petition calls on the agency to make a finding that emissions from aircraft endanger public health and welfare under the Clean Air Act, and argues that new rules could minimize fuel use, require more energy-efficient planes, and create incentives for using cleaner jet fuels.