There are more than 14,000 licensed pilots in the Washington-Baltimore areas and about 2,800 private plane owners, according to the Aircraft Owners and Pilots Association.

They fly from a number of airports big and small, the busiest of them being Manassas Municipal, with 196,000 takeoffs and landings annually, followed by the Montgomery County Airport (144,000) in Gaithersburg and the Leesburg airport (124,000).

Dulles International Airport actually handles more general aviation flights than it does commercial flights. In 1977 there were 109,883 general aviation flights to 628821 commercial ones. Those commercial flights, however, carried 2.7 million passengers; the general aviation flights carried 117,824 passengers.

Manassas Municipal Airport is planning to add a new runway next year, plus a full Instrument Landing System (ILS), the standard electronic landing guidance device for use in bad weather. That would make Manassas the first "small" airport in the region to have a full ILS.

If small-plane pilots want to practice ILS approaches and landings in this region, they have to do so at Dulles, Baltimore-Washington International or Andrews Air Force Base.

General aviation lobbyists have said for years that they would be delighted to stay away from the big airports if there were adequate "reliever" facilities that were instrument equipped.

Both the Federal Aviation Administration and the Metropolitan Wahington Council of Governments are studying the question of reliever airports for this area-and some likely candidates already exist. Two military fields-Andrews and Davison Field at Fort Belvoir-are well equipped and underused, according to FAA officials.

Another landing strip-Beltsville-is much coveted by the general aviation community but well protected by the U.S. Department of Agriculture, which owns it. The Beltsville strip is located in the middle of USDA's Prince George's County research center, and immediately adjacent to NASA's Goddard Space Flight Center. Any heavy use of that strip would foul up NASA's satellite tracking system, USDA officials said, and disturb Wildlife at the adjacent Patuxent Wildlife Refuge.