Lawyers for the City of Chicago and O’Hare Airport’s biggest airlines agreed once again Friday to delay a lawsuit over a multi-billion dollar expansion of the airport.

The delay comes as both sides continue to negotiate over how to proceed with the final phase of the O’Hare Modernization Project, which would add new runways to O’Hare.

Representatives from both parties met privately with Cook County Judge Richard Billick Friday morning. An airline spokesman wouldn’t offer any details, but to say the discussions continue.

United and American are suing the city to block the $3.36 billion project. The airlines would be on the hook for much of the cost, but they maintain that current air traffic levels don’t justify the expense.

Chicago Mayor Richard Daley’s administration has been trying to push ahead and break ground for construction next month. The city is trying to issue bonds to finance the last phase of the expansion, but the airlines say their approval is required.

Daley hasn’t been shy about attacking the airlines in the press, but his tone was more conciliatory on Friday.

“I really believe we’ve had good discussions,” Daley said.  “That doesn’t mean there’s some difference of opinion but in the long run I think - I firmly believe that these discussions have really helped everyone.”

Daley wouldn’t say whether he thought construction would begin on schedule. The mayor dismissed suggestions that the airlines are stalling negotiations until Rahm Emanuel becomes mayor in May - a suggestion Daley himself has made in the past.