United Has High Hopes for New O'Hare Runway

The new runway should allow an additional four or five hourly arrivals and reduce delays by 4% to 5%, but "we never said this was a major runway," Molinaro notes. Over the next several years, two more runways are planned, although funding has not been secured. The added runways are expected to reduce delays by about 30%.

Aviation consultant George Hamlin says that even without caps, O'Hare is a difficult place to set up shop. "American and United have the place locked up," he says. A low-cost carrier like JetBlue (JBLU Quote) could operate at O'Hare, but only minimally.

"If you are Delta, you might put in one or two flights, but you won't be mounting a major attack on Chicago," he contends.

Overall, experts say, delays at O'Hare are easier to address than those at the New York airports, because New York suffers from congested airspace, clogged by traffic at multiple airports and a high number of business jets. By contrast, O'Hare's congestion is largely a ground issue that can be addressed by more runways.

Still, consultant Mike Boyd says more help is required. "Once these airplanes get in the sky, they are still directed by an air traffic control system that is 50 years out of date," he says. "O'Hare runways could make a difference, but the real problem is getting airplanes to and from those runways."