Tests to see if National Airport's aircraft noise can be dispersed over a larger portion of the Washington area were put in a holding pattern yesterday by regional leaders.

The Metropolitan Washington Council of Governments' board of directors rejected a federal plan for a three-or-four month test of scattered flights. The flights, which are now concentrated in a corridor along the Potomac River, would have been spread more widely under the proposal. The changes would have significantly increased aircraft noise in lower Montgomery County, Falls Church, North Arlington and McLean, but decreased noise for residents living in the Cabin John area of Montgomery and in the area between Chain Bridge and the Capital Beltway.

Instead of adopting a plan drawn up by the Federal Aviation Administration, the regional board, by a 13-to-7 vote, supported a new study on scattered flights that would involve not only federal engineers but COG itself and a citizen group called Coalition on Airport Problems.

"This is another attempt to solve what is probably an unsolvable problem," said Fairfax County Supervisor Martha V. Pennino, a member of the COG board, in a lukewarm argument for more study. "But we should make another good faith effort."

Pennino and the citizen coalition argue that the FAA plan didn't really scatter flights equitably. The coalition has been fighting for a flight plan that would expose more people to flights, thereby lessening the exposure any one group would have to the aircraft.

If a compromise plan can be reached by the COG, the coalition and the FAA, testing of the new flight patterns could begin in August, Pennino said.