Though many airlines have tried to reduce their carbon footprints through technical innovations — like more efficient aircraft designs and biofuels blends — they have successfully resisted any regulation or taxation of their emissions.

In an unsuccessful lawsuit before the European Court of Justice last year, United States airlines argued in part that the European Union had no right to tax emissions on trans-Atlantic flights because they went into international airspace.

Airlines for America, a trade group for United States carriers, has proposed setting emissions targets for flights from now until 2020 and adding in financial penalties only later. “The problem with the European trading scheme is that it started with a market-based measure — a tax,” says Nancy Young, the group’s vice president for environmental affairs. “We would accept a market-based mechanism only as a gap filler, if we don’t meet our targets. And we will be saying that very strongly.”

She said the European scheme was “extremely burdensome” and would cost United States airlines $3.1 billion between 2012 and 2020, adding, “It takes money out of U.S. aviation and puts it into European coffers.”

But some in the industry contest that view. “I think airlines typically overstate how difficult this is,” said David Hodgkinson, former director of legal services at the International Airline Transport Association, an industry group, who now practices aviation and climate law in his native Perth, Australia. “I don’t get why opposition is so fierce given that this is relatively straightforward and the cost is typically low and passed on to passengers.”

He said that Qantas, the Australian airline, is going along with the European scheme, under which airlines must buy so-called carbon allowances if they exceed assigned annual emissions targets, which decrease year by year.

Some analysts estimate that the European program would add about $5 to the price of a typical trans-Atlantic flight. While that may sound minimal, Ms. Young of the airline association maintained that United States airlines operate on razor-thin margins. She said, “This may be the difference between loss and profitability.”