United Airlines is returning to Columbia Regional Airport, adding flights to Chicago and Denver starting Sept. 25.

Chicago's O'Hare airport is in the middle of dispute between United Airlines and American Airlines at a tense time for the airport and airline sectors.

COLUMBIA — United Airlines will return to the Columbia Regional Airport with flights to Denver and Chicago. The airline will have one daily flight to Denver and two daily flights to Chicago O'Hare, Columbia Mayor Barbara Buffaloe announced in a news conference Thursday afternoon.

BILLINGS, Mont. — The city of Billings, Billings Logan International Airport (BIL), in partnership with Visit Billings, the Billings Chamber of Commerce, and Big Sky Economic Development expanded service from United Airlines with the launch of a daily seasonal flight from Billings (BIL) to Chicago (ORD).

A legal battle playing out between American Airlines on one side and the city of Chicago and United Airlines on the other could shape the future competitive landscape at the airport.

United Airlines will return to COU on Sept. 25 with one daily flight to Denver and twice-daily flights to Chicago O'Hare.

On average, bookings from the United States to Europe on more than a dozen major routes for travel from June through August were down about 10% through early May, while bookings for travel from Europe to the U.S. were down 12%, according to aviation data provider Cirium.

With the start of Memorial Day weekend, many people in the Chicago area either got ready to head out of town or enjoy a packed slate of events in the city.