TAXPAYERS ACROSS the country should love this one: just as the administration, the airline industry and governments of this region have come up with a sound proposal to relieve the federal government of its expensive responsibility for operating and improving National and Dulles airports, a bill is introduced to authorize the spending of as much as $250 million in federal funds to fix up the two terminals. Why not let the proposed regional authority take over and float tax-exempt bonds to pay for the construction?

Sen. Ernest F. Hollings says he's worried about leaving these two entry points to the nation's capital "to the whims of any state government," adding that 'under this logic, the federal government should divest itself of Smithsonian museums, the Botanical Gardens and the National Zoo." If entry points are that endangered by state, local or private ownership, presumably Uncle Sam should purchase and maintain Union Station, the Trailways and Greyhound bus terminals and all the bridges across the Potomac. You never know what might happen in an emergency.

Whatever else they may do about the budget this year, it's difficult to believe that members of Congress will vote for such totally unnecessary federal spending. A far better alternative is the regional authority takeover proposal sponsored by Sen. John Danforth of Missouri, Reps. James Howard of New Jersey and Gene Snyder of Kentucky and members of Virginia's delegation to Congress. This measure reflects the recommendations of a special commission headed by former Virginia governor Linwood Holton and appointed by Transportation Secretary Elizabeth Hanford Dole.

The regional authority bill even enjoys the support of the airline industry, which has dropped all earlier objections in the interest of getting the proposal approved this year. The only airline still pushing for its own special-interest language is American Airlines, which for years has been trying all sorts of ways to expand National Airport's 1,000- mile limitation on nonstop flights in and out of there. Were members of Congress to buy this one for American, they would set off all sorts of flight- service changes they hadn't bargained on.

Congress should resist narrow pleadings that would wreck the bill and then stick taxpayers all across the country with the tab for two airports. Good fiscal sense and sound transportation policy point to the bipartisan regional transfer bill as a wise and timely move.