American Airlines said Thursday it has reached a compromise with the city of Chicago and will support the proposed $8.5 billion expansion at O’Hare International Airport.

The announcement comes two weeks after American objected to the deal at one of its major hubs over a proposed gate allocation it said would favor rival United Airlines, which also has a major operation in Chicago.

The proposed $8.5 billion expansion would add about 35 new gates to the existing 185. Airlines would foot much of the bill through higher rents and landing fees. At the start of 2018, United controlled 75 gates to American's 67, according to the airport.

American’s objections involved United being given priority on five existing gates at the space-constrained airport that will be freed up due to other airlines shifting their operations. The compromise announced Thursday doesn’t change the gate allocation for the planned expansion, but will accelerate the construction of three planned gates that will be available for use by all airlines.

“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,” American Airlines CEO Doug Parker said in a statement. “The mayor [Rahm Emanuel] and his team worked tirelessly and creatively to structure an agreement that keeps competition thriving at O’Hare.”