These are tough times for any industry that burns a lot of fossil fuel or emits a lot of carbon dioxide, and the air travel business does both. The airlines never gave it much thought before, but with sky-high oil prices and mounting concern about global warming threatening not just their bottom line, but their existence, they're getting serious about reducing the industry's carbon footprint.

"They’re definitely in bad shape," says John Scholle, an economist with Global Insight. "And going forward, things look bleak."

It is against this backdrop that executives from the U.S. commercial aviation industry gather later this week in Washington D.C. to plot a new course.

The Air Transport World Eco-Aviation conference marks the first time the industry has come together on such a large scale to talk about the environment. The conference underscores the severity of the issues facing commercial aviation and the need to begin addressing them collectively and quickly.

With airline passenger growth rates and aircraft emissions expected to double by 2020 and 2030, respectively, time is of the essence.

Rising fuel prices have airlines around the world hemorrhaging money, and losses could hit $6.1 billion this year. Governments on both sides of the Atlantic are threatening to crack down on emissions. And environmentalists are lining up against an industry that, like the automakers before it, has long considered environmental responsibility an afterthought.

Commercial aviation has seen tough times before, experts say, but never before has the challenge been so great and the prospects so grim.

Topping the conference agenda is determining how big a role government should play in regulating aviation-related emissions. This is an issue of mounting importance now that the European Union says airlines must join its carbon trading program and with environmentalists petitioning the Environmental Protection Agency to regulate aircraft emissions. It is, they say, the only way to get the airlines to clean up their act.

"Market mechanisms for cutting pollution won't work," says Danielle Fugere of Friends of the Earth, the group that filed the petition.

The airline industry disagrees, of course, and says it has increased fuel efficiency 110 percent since 1978. It also claims to have reduced emissions 4 percent between 2000 and 2006, despite a 12 percent increase in passengers and a 22 percent climb in cargo. "Airlines are already motivated to reduce fuel burn and the resulting greenhouse gases as much as possible," says Nancy Young, vice president of environmental affairs for the Air Transport Association.