With strong backing from groups supporting U.S. airlines and despite opposition from climate change advocates, President Obama yesterday signed legislation directing the secretary of Transportation to prohibit carriers from taking part in an E.U. emissions program.

A White House spokesman said the E.U. program was the "wrong way" to reduce carbon emissions. The spokesman told reporters that administration officials would continue talks with the International Civil Aviation Organization (ICAO), the U.N. group overseeing aviation affairs, because there is a commitment to reduce "harmful carbon pollution from civil aviation both domestically and internationally."

Earlier this month, the European Union halted the program, which is part of the carbon-trading regime known as the Emissions Trading System, or ETS, a day before the House voted on the bill. Under the ETS plan, carbon emissions from airplanes would be capped at 97 percent of 2004 to 2006 levels. For starters, airlines would have to buy 15 percent of their emissions certificates at auction.

The bill signed into law directs the Department of Transportation to prohibit U.S. civil aircraft operators from taking part in the E.U. program if it is determined the program would cause a detriment to the public. In arriving at such a determination, officials must consider the financial impact the ETS could have on airlines, workers and the environmental and energy sectors.

The law also directs DOT, the Federal Aviation Administration and related agencies, to study ways to reduce airlines' carbon footprint.

Before a voice vote passage by the House this month, the Senate passed the most recent version of the bill in September. Last year, the House passed a similar bill under suspension of the rules by voice vote.

Sen. John Thune (R-S.D.), the bill's sponsor, likened the signing of the legislation as a victory for airline passengers who will be shielded from "this illegal tax, freeing up billions of dollars that can instead be invested in creating jobs, modernizing or purchasing new aircraft and stimulating our own economy."

Airlines for America, which opposed the program, applauded Obama's decision to sign the measure.

"Working within the framework of the International Civil Aviation Organization, the United States will continue to lead the effort to secure a policy that will meet the twin goals of allowing for industry growth and continuing improvements in fuel efficiency and reduced emissions," said Nicholas Calio, president of the group.

Some prominent environmental groups, however, said they wished Obama had vetoed the bill. Doing so, they argued, would have shown a commitment to pursuing climate change initiatives during the next four years.