Foes of National Airport have renewed their campaign to lower the number of flights there. Their efforts come as airlines are preparing to expand operations at National in response to the end of restrictions imposed after the air controllers' strike last year.

U.S. Transportation Secretary Drew Lewis will study the calls for fewer flights, a spokesman said.

Many federal officials believe that the issue was settled last fall when a detailed policy regulating noise and traffic levels was put in place after years of debate and negotiation.

However, civic activists in the neighborhoods along National's flight path say the policy was only a "first step" and are raising money to renew the fight. Rep. Frank R. Wolf (R-Va.), who argued for the policy last year, and at least two other congressional candidates in Northern Virginia are also seeking to tighten the policy.

The policy provides that scheduled airline landings and/or takeoffs will not exceed 37 per hour, slightly lower than the prestrike levels. It restricts noise and limits total passengers to 16 million a year. It also tries to promote Dulles International Airport, which has unused capacity.

However, when the plan came into effect last November, the controllers' walkout already had forced the Federal Aviation Administration to reduce flights well below the policy's levels. In effect, that made the new policy a growth policy.

Critics' concern grew last week when the FAA, which owns and operates National and Dulles, announced it would lift the strike limits as of Nov. 1 and allow airline operations to rise to the policy ceiling--meaning about 30 more takeoffs and/or landings a day. Airlines met this week at a District hotel to decide how the extra capacity will be divided up.

In response, Wolf wrote to Lewis calling for the levels to stay where they are. The strike showed that a quieter traffic schedule at National Airport was not harmful, Wolf said in an interview. "Why not freeze it now and then allow those additional flights to go out to Dulles?" he asked.

Speaking privately, some federal officials said the policy took years to achieve and is not likely to be changed. It grew from years of studies, public hearings, and negotiations with airlines, civic groups and members of Congress who have opposed attempts to cut traffic at National.

Wolf, who backed the airport policy last year as the best that could be achieved, said his current stance is not an attempt to win votes. "I've been consistent on this," he said." . . . We've always said it the policy was a good first step."

Two other Northern Virginia candidates for the House, Herbert Harris, a Democrat seeking the 8th District seat, and Ira Lechner, a Democrat in the 10th District race, have also criticized the lifting of the strike limits.

Meanwhile, the Coalition on Airport Problems (CAP), an umbrella group linking concerned civic organizations, has embarked on a fund-raising campaign. A questionnaire and request for money sent in May to 10,000 homes in the flight path received a good response, according to vice president Bonnie Newlon. She declined to disclose how much money it had generated. CAP plans to survey another 10,000 homes soon.

In its campaigns against the airport, CAP is now stressing alleged safety deficiencies at National. "There's a sense of urgency since the crash that did not exist before," said Newlon, referring to the Air Florida crash in January. The FAA says National is safe.

CAP and Wolf also condemned FAA plans to spend $1.3 million studying how parking lots, buildings and other facilities at National might be improved. Critics argue that money should not be spent to make National more attractive when there is unused capacity at Dulles.

Dulles, which was not among the 23 airports restricted after the strike, has logged an increase in traffic in the last year. This will be threatened by increased capacity at National, CAP and Wolf maintain.

With passenger and plane levels now set by the policy, airport manager Jim Wilding responds, National should try to improve service for those levels and may need to modernize.

Opened during the propeller era of the 1940s, National has long been criticized as substandard for the volume of traffic it handles.

Meanwhile, efforts to promote Dulles continue. Cathy O'Connor, a former Pan American World Airways flight attendant who was based at the airport, turned over to Wolf and Rep. Stan Parris (R-Va.) this week the signatures of 9,000 people who favor more service at Dulles.

The Washington Dulles Task Force, a nonprofit group formed in May, is trying to hire a staff of five before beginning a concerted promotional drive. It is funded by grants from the federal and Virginia state governments and private businesses that have an interest in greater service at Dulles.