One proposed a rule that would require altitude-reporting devices on all planes operating within 30 miles of the nation's 23 most congested airports.

So the time a flight is scheduled at congested airports can make a big difference in on-time performance, no matter what carrier is chosen.

The study, which covered the 30 most congested airports plus Memphis, a cargo hub, also showed that fewer than half expected to build more runways.

There are alternatives to the most congested airports.

"Take Tokyo, which is a very congested airport," he said.

But budget airlines claim better punctuality by using less congested airports.

Initially, the airline avoided flying to Mexico City because of its congested and expensive airport.

Yet avoiding airport congestion can be as simple as bypassing congested airports.

Several said they needed a larger plane to serve congested airports like Heathrow outside London.

The number of air traffic delays rose sharply last year, especially at the nation's five most congested airports, Government officials reported yesterday.