This week both U.S. Senators from Illinois will be meeting with the heads of United and American Airlines.

The companies filed a lawsuit against the city of Chicago regarding the second phase of a project to expand O’Hare International Airport. The airlines say the lease agreement they have with O’Hare gives them voting rights on capital projects, and the city has violated that.

Senator Mark Kirk, a Republican, said he and Sen. Dick Durbin, a Democrat, want to help the two sides come to a compromise.

“Our job is to be mediators here. Most lawsuits are settled. And my hope over time is we can be as helpful as possible to both sides to settle this in a way that maintains momentum for the O’Hare Modernization Project,” Kirk said.

Officials for the city’s Department of Aviation say timing is essential in securing funding for the project. They said they had the legal right to move forward.