New York Air yesterday took another step closer toward starting its low-fare service between Washington and New York.

In a two-day meeting of representatives of the 23 airlines operating out of National Airport, New York Air gained 36 slots spread throughout the day, which will enable it to begin most of the service the airline wants to start on Dec. 14. New York Air officials hope to fill what gaps remain if other airlines give up slots -- the industry term for takeoffs and landings -- they now plan to use.

New York Air's nine round-trip flights a day to LaGuardia Airport will start with fares 20 percent to 50 percent below the Eastern Airlines shuttle price of $60 each way. New York Air plans to charge $49 each way for weekday flights until 7 p.m., and $29 each way for flights after 7 p.m. and all day weekends.

The meeting of airline representatives completed work on schedules for flights in and out of National that, in general, will be operated from Dec. 1 to April 26.

Much of the work was done under the auspices of the Department of Transportation, which had come up with a plan for allocating the limited slots at National -- 40 an hour for the commercial airlines -- when the airlines failed to agree on a formula. Under DOT's plan, five airlines operating at National were forced to give up a total of 12 slots in December. In addition, the dozen airlines with the most flights under the November schedule, including the five giving up slots, were required to move one flight to 10 p.m. or to give it up. The reductions had to be in certain time periods set aside by DOT.

These actions combined to make way for nine of the 10 round-trip flights a day New York Air wanted as well as some new or expanded services by Air North, Midway Airlines, Empire Airlines and Mid-South Airlines. These airlines selected their new flight hours, in an order according to a DOT formula, from the flight hours vacated by the incumbent airlines.

Although the process was mandated by the DOT, each airline complained that the actions it took were being made under duress. "I don't see where you get those numbers for us," Braniff Airways' David Cummings protested when he was called on to make the first two deletions. "I'm not doing this of my own free will."

DOT officials made it clear they didn't like the plan much better than the airlines. "We are not here to justify the rule -- we are here to implement it," beleaguered Gregory Wolfe responded. .AIRLINES, From D7>

A couple of the airline representatives indicated that they may join Northwest Airlines in already filed legal action challenging DOT's right to allocate slots, or may file their own cases.

After the DOT process was completed, the airlines stayed on, under the aegis of their scheduling committee, to see if some could trade slots with others to bring their schedules closer into line with what they hoped to operate.

The airlines have antitrust immunity, granted by the Civil Aeronautics Board, to exchange slots with others through the committee process. Trades outside the committee that are not made available to all equally do not have immunity.