CONTINUING WHAT HAS become a swift pace of action on matters of longstanding concern to Greater Washington, Transportation Secretary Elizabeth Dole has moved to strike a better balance between the uses of National and Dulles International airports. Her proposal, issued for public comment before consideration as a formal regulation, would not affect a single flight now in operation at National; but it would shift more future air traffic to Dulles--which is how the balance would be struck.

The policy, which was vigorously sought by Virginia Rep. Frank Wolf and a bipartisan group concerned about congestion and other inconveniences at National, would set an annual maximum number of passengers either at 14.8 million, or at somewhere between 14.8 million and 16 million as determined by the annual passenger volume forecast in January 1985 by the Federal Aviation Administration. This would have no immediate effect because, at last count, about 13.3 million people were using National every year, and the cap right now is 16 million.

There are likely to be objections from some airlines that always seem to oppose even modest attempts to bring some order to airport policies. But Mrs. Dole's proposal is a moderate, logical next step to an earlier airport agreement negotiated between DOT and Congress. And there are other moves aimed at improving service to smaller communities within short-haul distance of National; promoting quieter aircraft there; and improving ground-transportation access to Dulles.

For short-takeoff-and-landing operations--commuter carriers--Mrs. Dole is authorizing two additional slots an hour for a nine-month trial period. Other forthcoming changes at National will see the landing of the 757 aircraft, which, though it has more seats than the 727, is considered quieter. If so, and coupled with the cap on passengers, it wouldn't mean more traffic; instead it could mean people arriving in larger groups on fewer, quieter flights.

As for Dulles--and getting to it--that 3.7-mile extension linking the access road with I66 is scheduled for completion in September. It should cut considerably the driving time between Dulles and downtown Washington. Sometime next year, the Dulles commuter toll road should be built, too. In the meantime, the FAA is acquiring 12 to 15 new airport buses.

This coordinated approach to a balanced air traffic policy not only looks to the future sensibly, it also addresses concerns that have plagued residents and travelers in this region for too long in the past. Adoption of these policies cannot come too soon.