I write in response to the article "National Airport Review May Lead to More Flights" {news story, Nov. 1} to reassure those concerned about additional flights at Washington National Airport. As chairman of the House public works and transportation subcommittee, which hammered out the legislation in question, I want to assure Post readers, and especially those affected by airport noise, that the new legislation will not result in increased flights or increased noise at National.

The article, and its named and unnamed sources, gave the impression that the new Airport Noise and Capacity Act of 1990, passed in the last hours of the 101st Congress, would make possible more flights at Washington National and three other airports, endangering safety and increasing congestion and noise. These concerns were justified with respect to the bill that the Senate had passed earlier, but the House was able to correct this flawed provision in the final conference agreement.

The new law requires the secretary of transportation to consider more efficient methods of allocating existing capacity at high-density airports to facilitate service by additional airlines.

The use of the term "existing capacity" means that the secretary shall not consider increases in hourly or daily flights at the high-density airports. The number of hourly flights would continue to be limited by the Federal Aviation Administration's slot regulations and, in the case of National Airport, by law. Contrary to the suggestion in The Post's story, the cap of 37 airline flights an hour at National could not be evaded by averaging -- such as scheduling 39 flights for some hours and 35 flights for others.

I would also note that the agreement only directs the secretary to initiate a rule-making proceeding, not to change the existing allocation of slots. The secretary is not directed to reach any particular decision in the rule-making and, in fact, is ultimately free to decide that no changes should be made in the slot allocation system.

Post readers should also know that the conference agreement will greatly reduce noise by requiring airlines to replace 85 percent of their noisiest aircraft by mid-1999 and the remaining 15 percent no later than 2003. This phaseout of Stage 2 aircraft, the oldest and noisiest airplanes, will reduce the number of persons living in noise-impacted areas near airports from 3 million today to about 1 million early in the next century.

JAMES L. OBERSTAR U.S. Representative (D-Minn.) Washington