The Arlington County Board endorsed the concept yesterday of transferring National and Dulles International airports to a regional authority as proposed in federal legislation, but said the legislation should include a provision giving the county the power to tax National.

Pointing to the $695,000 in taxes that Loudoun County received last year alone from the sprawling Dulles facility within its borders, the Arlington board said the county could collect as much as $1.3 million annually if granted permission to tax Arlington-based National.

"It's a basic boilerplate issue for us," said board member Albert C. Eisenberg of the taxation proposal. Phyllis Fordham, the county's staff specialist on National, said Rep. Frank R. Wolf (R-Va.) will offer an amendment to the federal transfer legislation to allow the county to tax National. Congressional hearings on the legislation will take place later this month.

Arlington's ultimate support of the proposed transfers is considered important because National Airport is based in the county.

Unlike Loudoun County, which collects real estate and personal property taxes at Dulles, Arlington cannot tax National Airport because of a 1948 pact between Virginia and the federal government. When the state ceded the land National now occupies to the federal government, it waived its right to collect all but a few taxes there, primarily sales taxes on food, car fuel and cigarettes.

The transfer legislation drafted by the U.S. Department of Transportation would shift control, and eventually the ownership, of the two airports from the federal government to an 11-member regional authority that could sell tax-free revenue bonds to operate and improve the airports.

Because both airports are in Virginia, the state would have five members on the authority, while the District would get three, and Maryland two. The president would also appoint a member.

"The legislation offers an opportunity for Arlington County to take charge of its own destiny," said Donald Lucas, an airport activist. "The airport is in our own back yard. As responsible citizens, we should be given the authority and responsibility to run this airport."

Another point raised yesterday by the board was eminent domain. County Attorney Charles G. Flinn said he is concerned that those powers are too broad in the drafted bill, and should be limited so the authority can take land only to provide additional space for airport purposes and not as a revenue-raising tool.

On other issues, the board repeated its concerns about the annual passenger ceiling allowed at National and the limitations on the hourly number of flights in and out of the airport.

The proposed legislation would eliminate the current annual passenger cap of 16 million persons, and would not allow an authority to lower the current ceiling of 37 planes an hour. Board members said they believed an authority should have the power to set limits.

Although similar attempts to sell the two airports, the only federally owned commercial airports in the country, have failed in the past, this most recent proposal is given a better chance of succeeding, despite some congressional opposition.