CHICAGO (CBS) — Two weeks after American Airlines announced their opposition to an $8.5 billion plan to expand the terminals at O’Hare International Airport, Mayor Rahm Emanuel’s office said it has reached an agreement to bring American on board.

The dispute with American had threatened to delay the plan to add dozens of gates at O’Hare. The City Council Aviation Committee was meeting Thursday morning to review the expansion plan.

Last month, American had accused the Emanuel administration of cutting a secret deal with United Airlines to give Chicago’s hometown airline five extra gates as part of the expansion plan.

United said the agreement on five additional gates was no secret, and was made 18 months ago in response to a 2016 deal with the city to add five new American Airlines gates at O’Hare. Those gates are expected to open in April.

To settle the dispute over gates for United and American, the mayor’s office said it has agreed to speed up construction of three shared gates that would be available to American and other airlines at O’Hare.

“This agreement is a watershed moment for Chicago, and it means we will create tens of thousands of jobs for Chicagoans from every part of the city, generate billions of dollars in economic development and strengthen our city’s economy for generations,” the mayor said in a statement. “O’Hare will compete with any airport in the world, and Chicago residents and visitors will have more options and a vastly superior traveling experience.”

The mayor’s office also provided statements from United and American praising the expansion agreement.

“This agreement not only gives O’Hare a competitive edge against other airports, but also ensures competition thrives between airlines, so that – in the end – customers win. We look forward to continue growing at O’Hare, which is already our busiest hub, and serving the City as one of the region’s largest private sector employers,” United CEO Oscar Munoz said.

“This landmark plan for a redeveloped O’Hare will transform the airport experience for travelers and allow American Airlines to continue to invest and grow in the city of Chicago,” said American Airlines CEO Doug Parker. “We are strongly supportive of this agreement because it is what is best for the city of Chicago, our 9,300 Chicago team members and our customers.”

The expansion deal would add dozens of gates at O’Hare by replacing Terminal 2 with a new Global Terminal with wider concourses, renovating the other three terminals, and adding two new satellite concourses.

The deal would be funded by higher fees charged to the major airlines. No taxpayer dollars would be used for the project.

The airlines’ current 35-year lease at O’Hare is set to expire in May.

Under the proposed expansion plan, the number of gates at O’Hare would increase from 185 to 220, and 3.1 million square feet of new terminal space would be added – a 72 percent increase.

Construction would take eight years, with completion scheduled for 2026.