House and Senate conferees yesterday delayed until April 26 -- and perhaps forever -- cuts in jet airliner flight at Washington National Airport.

At the same time, the conferees directed that Transportation Secretary Neil Goldschmidt "should go ahead" in admitting jumbo jets to the airport and in implementing other elements of his airport policy while Congress debates the single question of a proposed hourly reduction in jet airline flights from 40 to 36.

The vagueness of the conferees language left Department of Transportation officilas uncertain as to whether they were being ordered by Congress, in effect, to give the airlines everything they want no change in the number of flights permitted, the admission of the more efficient and larger jumbos, and the addition of nonstop flights to such cities as Birmingham, New Orleans, Kansas City and Tampa.

There was no uncertainty however in the minds of Sen. Thomas F. Eagleton (D-Mo.) and Rep. Robert B. Duncan (D-ore.), who were the ranking conferees when the question came up during discussion of the Department of Transportation's annual appropriations bill.

"My understanding is that it is the intent of the Congress that the rest of the plan go forward," Eagleton said in an interview.

Yeah," said Duncan, "all the other parts go ahead."

If this is the final resolution of the long-smoldering National Airport issue, it is certain to enrage noise-weary citizens who live along National Potomac River flight paths.

The confusion in the minds of DOT officials comes because if Goldschmidt's policy is stripped of the hourly reduction of flights, other elements of the policy appear to be contradictory.

That is because Goldschmidt's policy also prohibits the airlines from scheduling either takeoffs or landings at National after 9:30 p.m. (the current voluntary curfew is 11 p.m.) and says that no more than 17 million passengers may use National annually. The current total is about 15 million.

Taken together, those two action inevitably would have the impact of reducing flights, something the conferees said DOT cannot do, at least until April 26. Goldschmidt's policy if unfettered by congressional interference, was to take effect Jan. 5.

"We're just going to have to wait and read the final conference committee report, then decide," said Robert J. Aaronson, associate administrator of DOT's Federal Aviation Administration. Goldschmidt himself, who had participated actively in the intense preconference lobbying on the issue, had no comment. He sent a letter to the conferees earlier in the day, however, that said, "We are not prepared to proceed with certain elements of the policy in January while the reduction in flights is deferred."

The conferees were faced with the issue because of an amendment added by Sen. John Melcher (D-Mont.) to the Senate version of the DOT appropriations bill. That amendment, adopted 47-29, would have postponed the entire airport policy until April 1. The April 26 date was chosen by the conferees yesterday because that is the first day of Daylight Saving Time, when the airlines make major schedule changes.

Duncan and other House conferees seemed to think they were actually helping Goldschmidt's policy along, but DOT officials and other who want something, anything, done to break the long airport impase, felt otherwise. With the delay until April 26, there will be plenty of time for the next Congress to scrutinize (and possibly reject) the proposed reduction in flights, or the entire policy. If that happens it is also possible that yet another secretary of transportation will have to be educated on the issues and go through another round of hearings.

The National Airport issue has been tied up in DOT or the federal court system for the last seven years. During that time, passenger use has continued unabated at a terminal designed for the 1940s and served by a road network created by the National Park Service. tAll attempts to limit passenger growth, plus all attempts to improve the terminal and its access roads, have been held illegal because of the lack of a policy.

Duncan said that the conference report will contain language suggesting that the airport may not have the ground-handling facilities needed to deal with jumbo jets and that that part of the policy should proceed slowly. However, Eastern Airlines was flying tests with its jumbo a300 Airbus at National last Saturday and is ready to go tomorrow if it gets the clearance.

In a related action on the DOT bill, the conferees appropriated $16.2 million to construct a highway connecting the Dulles Access Road with Interstate 66 inside the Beltway. The lack of a high-speed freeway from downtown Washington to Dulles has long been cited as one of the major reasons the airlines want to use National Airport instead of Dulles.