They said in April they would limit both airlines at O'Hare to 2,708 arrivals and departures a day, from May 17 through October 24. Getty Images Getty ImagesSo in response to this, United Airlines is delaying 10 routes from O'Hare:Guadalajara International Airport (GDL)University of Illinois Willard Airport (CMI)Kalamazoo/Battle Creek International Airport (AZO)Capital Region International Airport (LAN)La Crosse Regional Airport (LSE)Central Illinois Regional Airport (BMI)Tri-Cities Airport (TRI)Erie International Airport (ERI)Rochester International Airport (RST)Marquette Sawyer Regional Airport (MQT)Before the FAA's restrictions earlier this year, which were in part due to other issues like air traffic control staffing, the airlines had been planning to fly 15% more flights this summer than last. United and American continue to battle out market share at O'Hare, but the airport itself has had several issues lately, including weather-prompted delays and ground stops and runway construction. United Airlines has said that it hopes to resume operations once the FAA regulation expires. United and American airlines are what's being called an "air war" for prevalence at O'Hare.