American Airlines opposes O'Hare expansion alleging 'secret' United advantage

— -- By all appearances, American Airlines was signed on and ready to proceed with Chicago mayor Rahm Emanuel's $8.5 billion expansion of O'Hare International.

But just hours before Emanuel's formal unveiling of the plan, which would increase the terminal's square footage by 60 percent, American announced its opposition, citing concerns about what it called "a secret provision, inserted at the last minute, awarding additional gates to United."

"The United gate deal would undermine competition," American said in a statement. "The United gate deal creates a clear winner, United, and clear losers: namely, competition, Chicago travelers, and American Airlines."

Calling American's claim "disingenuous," a United Airlines spokesman denied allegations of a "secret deal" and said American has been aware of the plan for over a year.

American - which is refusing to re-up its lease, set to expire in May, under these conditions - is O'Hare's second biggest tenant, after rival United. The airline said it wants Emanuel to "re-level the playing field."

"I want to be clear I am not picking one airline versus the other," the mayor shot back Wednesday. "Everybody was negotiating with and in good faith to reach an agreement. That has been accomplished, and we are going to move forward as a city and city council to secure that effort."

American says it urged the city to consider what it called a "compromise" - the construction of three additional gates to be awarded to American - a proposal it said was dismissed "without explanation."

In addition to increasing gate capacity, the planned expansion would incorporate new security screening to reduce passenger wait times and several new baggage handling systems, according to the mayor's office.

By 2026, the airport expects to see daily passenger load increase, from nearly 80 million to nearly 100 million.

"This is about positioning Chicago to compete with Beijing, Paris and Abu Dhabi, not about positioning in the decades-old competition between two airlines," Emanuel's spokesperson told the Associated Press. "We are going to add more gates, build a new global terminal, improve runways and create 60,000 jobs in the process."

WLS' Ravi Baichwal contributed to this report.