The Federal Aviation Administration reported yesterday that flight delays on the nation's commercial airlines dropped dramatically in September compared with the same month a year ago.

During September, the airlines reported an average of 886 delays of more than 15 minutes per day -- down 41 percent from the daily average of 1,496 a year ago.

The Department of Transportation is expected to release its monthly compilation of airline passenger complaints today, which will also show improvements in service -- an increasingly touchy subject for the airlines.

According to the FAA, delays in September also declined more than 2 percent from the number of delays recorded in August. It was the fourth month in which the airline industry improved its on-time performance. For the year to date, flight delays were down by 8 percent despite a 5 percent increase in the number of flights handled by the FAA's air traffic control system.

Two major factors produced the improvement, according to FAA Administrator Allan McArtor and airline industry officials. In February, the FAA expanded its East Coast air traffic control plan, adding new routes to reduce flight delays at the three major New York area airports -- John F. Kennedy International, La Guardia and Newark International. Approximately a third of all delays occur in the New York area.

In addition, the airlines began publishing what they called "more realistic" schedules. Some airlines had reported unrealistically short flight times to gain a market advantage.

Airline service has emerged as the key issue in the industry this year, with airlines bragging about their own service and dumping on competitors in advertising.

On Monday, the House of Representatives approved by a voice vote a bill designed to call the airlines to account for bad service by requiring them to compensate passengers for late-arriving luggage with free airline tickets and by imposing a fine of $10,000 on airlines that cancel flights for reasons other than safety.

The bill would require the airlines to provide a free one-way ticket on the route being flown for passengers whose baggage is more than two hours late and a round-trip ticket for passengers whose baggage arrives more than 24 hours after they do.

The bill also requires airlines to report on a variety of service issues, including flight delays and cancellations and baggage-handling problems. It would also require DOT to establish airport capacity levels for takeoffs and landings at 41 large airports.

The airline industry generally opposes the legislation. "There are some things in there that would be pretty tough to make work without costing a lot more time and energy from both the airlines and the government, and that's counterproductive, we think," said William Jackman, spokesman for the Air Transport Association.

Former DOT secretary Elizabeth Hanford Dole wrote the House Committee on Public Works and Transportation in September warning that DOT would probably recommend a veto of the bill if it passed.

The Senate is expected to act later this month on a similar but less far-reaching bill.

In August, hoping to head off action in Congress, six major airlines agreed to attempt to reduce delays for most of their flights or face fines of up to $1,000 per flight per day.

Then in September, DOT ordered major airlines to provide statistics about lost baggage and flight delays. The first reports are due Oct. 15.