The Department of Transportation announced yesterday that it will allow the nation's airlines to buy and sell landing rights at 22 major airports where flights have been restricted since the air traffic controllers' strike last August. Washington's National Airport is one of them.

DOT said the airlines will have a 30-day period in which to transfer airport slots--as the landing rights are called--as well as their current authority to have flights pass through 20 restricted air traffic control centers that handle intercity air traffic. Under the program, slots presumably could be traded, sold or bartered for other goods and services.

DOT's decision to allow the airlines to sell slots reverses an earlier decision made by the Federal Aviation Administration. A month ago, Donald R. Segner, FAA Associate Administrator for Policy and International Aviation, rejected a proposal from Southwest Airlines to buy two slots at Las Vegas from Air Nevada to begin some new service. At that time, Segner wrote Southwest that arrival rights at airports are "not property rights" and that to permit the airlines to sell them would "not be in the public interest."

M. Lamar Muse, chairman of Muse Air, an airline fighting for its life in Texas, said last night that DOT's plan is unlikely, as a practical matter, to help the new entrants that need additional slots to expand and grow. Few usable slots will be available, and if they are, they will add to the expense of doing business. "They have by this action put property values on air space, but not for those grandfathered in," he said. "How am I going to compete with someone who got their slots for nothing?"