With the change to daylight saving time later next month will come some new and changed air services to the Washington area, including the arrival of Western Airlines to two area airports.

Western will begin service from both Dulles International and Baltimore/Washington International airports on May 1 as part of a general restructuring of the airline's route system. The new flights are in addition to its current twice-daily flights between Washington National and Los Angeles with a stop in Minneapolis.

With its new schedule, Western will make one round trip a day between Dulles and San Francisco, with a stop in Salt Lake City, which the airline plans to make a major hub. The Los Angeles-based airline also will operate two round-trip flights each day from BWI. Both will fly to Minneapolis; one will go on to San Francisco, and the other will go on to Salt Lake City.

Beginning April 25, when daylight saving time starts, New York Air will retime its shuttle service between Washington and New York, offering flights to New York on the half-hour and flights from New York here on the hour. It is currently the reverse.

After the change, if a passenger gets to National after the hour, he or she can use NYA instead of wait for "other service which departs on the hour," a NYA announcement said, without mentioning by name its Eastern Air-Shuttle competition.

Both services to New York leave Washington on the hour now, eliminating the possibility that passengers who missed one could try the other. In New York, the Eastern shuttle now leaves on the hour and NYA on the half-hour, but passengers are less likely to go from one to another airline since they occupy different terminals, an official explained.