Government efforts to persuade airlines to reduce flight schedules at Chicago's O'Hare International Airport have yet to ease congestion there, the Federal Aviation Administration's top official said yesterday, and she said more carriers need to cut back.

"If we could get all the carriers to participate," the problem might be brought under control, said Federal Aviation Administrator Marion C. Blakey. "It's not in anyone's interest to have meltdown at O'Hare."

As airline traffic returns to levels not seen in years, the critical connection point at O'Hare has buckled under the surge, which leads to delays across the nation.

American and United airlines, O'Hare's biggest operators, have twice agreed to cut summer flights there, but other airlines added flights to take their place, Blakey said. United and American compensated by adding flights immediately before and after peak periods.

In May, O'Hare ranked last among major airports in the percentage of flights arriving on time, with just 60 percent of its flights staying on schedule. Bad weather caused some of those delays, but congestion exacerbates the problem, Blakey said.

By comparison, 78 percent of flights arriving at Washington's Reagan National Airport were on time, and 76 percent of flights at Baltimore-Washington International met that goal, according to the latest figures from the Department of Transportation.

The FAA is supposed to stay out of scheduling decisions because Congress deregulated the industry in 1978. But under a 2003 law, the FAA was given the authority to call meetings with airlines in an effort to ease congestion during peak hours.

Blakey said she has asked other carriers that operate at O'Hare whether they would consider voluntary cuts, but the Department of Transportation must decide whether to engage in official talks.

Some people involved in the industry are wary of such government involvement because they consider it improper federal intervention in the free market.

"It is a form of regulation," said Kevin P. Mitchell, chairman of the Business Travel Coalition. "I don't know where you stop that once you start . . . By the end of the summer, Dulles could be a real candidate."

The airline industry's chief lobbyist said airlines support voluntary cuts to reduce delays at certain airports, but only if they involve all carriers. "We recognize that the effectiveness of voluntary actions is only really effective if the FAA sort of helps by discouraging other carriers from jumping in to fill the void," said James C. May, president of the Air Transport Association, which represents airlines.