Illinois U.S. Sen. Dick Durbin says it could be hard to get any more federal money to help expand O’Hare International Airport.

United and American Airlines are suing the City of Chicago to delay the multi-billion dollar project. After a fruitless meeting with Chicago Mayor Richard Daley and Secretary of Transportation Ray LaHood, the carriers released a statement saying talks remained at a standstill, but they’d be open to exploring ways to get more federal money to help pay for runways.

But Durbin, who’d been working with Illinois Republican U.S. Sen. Mark Kirk to mediate the dispute over O’Hare, said getting more federal funding could be a tough sell in Washington.

“We’re facing a terrible deficit,” Durbin said Friday. “There’s not a lot of money coming to these agencies, even the Department of Transportation. So whatever they can do - and I don’t know what they can, or what it might be - it’s gonna be fairly limited by the deficit situation we face.”

Durbin said the federal government has already promised more than $1 billion for the O’Hare Modernization Project.

He said it’s a good sign that the airlines announced Thursday they’ve put their lawsuit on hold while negotiations continue, and remains optimistic that the city can break ground on the final phase of the project this spring.

United and American say they’d end up paying for about $2.3 billion of the project’s $3.4 billion cost. But they say current air traffic levels don’t justify the expense.