The trade group representing the nation's major airlines renewed calls Wednesday for a new runway at O'Hare International Airport to increase capacity and end delays that data show were the nation's worst last year.

The Air Transport Association said planning should start immediately on a new 7,500-foot runway that would be built parallel to two east-west runways to allow three streams of planes to land simultaneously in any weather conditions.

When visibility falls below prescribed safety minimums, O'Hare's air-traffic controllers must use only two runways for arriving planes because the airport's seven runways intersect.

The Air Transport Association said construction of the new runway, which would require the reconfiguration of some of the runways and taxiways, could begin as early as 2005 and be completed in 2008. It estimated the cost at $2 billion.

The association and the carriers it represents have made similar proposals in the past, but efforts to expand O'Hare have been stymied by opposition from nearby suburbs and a stalemate between Mayor Richard Daley and state officials over how to address the region's aviation capacity needs.

Chicago aviation officials have embarked on a $3.7 billion expansion of O'Hare's passenger terminals, but the city maintains that the airport has adequate runway capacity until 2012.

Data show O'Hare had 87,939 flight delays and 19,318 cancellations in 2000--more than any other airport in the nation.