Presidential Airways will begin providing connecting service to United Airlines flights from Washington Dulles International Airport on Feb. 6 under a marketing agreement announced by the two airlines yesterday.

The agreement appeared to be a boost for Presidential, which has yet to turn a profit in more than two years of operation.

The announcement also underscored United's commitment to building its hub at Dulles -- an East Coast center of operations from which the Chicago airline competes with Continental Airlines at Newark, American Airlines at Nashville and Raleigh-Durham, and Delta and Eastern at Atlanta.

The announcement comes two weeks after Dulles-based Presidential announced that it was ending a similar marketing arrangement with Continental Airlines under which it provided service as Continental Express. At the time, the airline said it would repaint its planes with the Presidential logo and resume scheduled service under its own name, as it had originally.

Instead, the airline will paint its planes with United's orange, red and blue colors and fly as United Express.

Harold J. (Hap) Pareti, president and chief executive of Presidential, said that talks with United had begun after Presidential and Continental announced the end of their relationship. "This agreement was not in place at the time," he said. "We felt we had to make the transition. We felt if we had to go it alone, we could."

When Continental and Presidential announced their marketing agreement a year ago, Continental said it planned to make Dulles a major hub. In the year that followed, however, Continental reduced service from the Northern Virginia airport as it increased service from Newark.

At the same time, United increased its service from Dulles to 87 departures a day. Presidential operates 50 flights a day from the airport, while Continental now has fewer than 40 flights daily from Dulles.

Under the five-year marketing agreement Presidential will provide connecting passengers to United from the generally smaller markets it serves. Both airlines' flights will be listed and ticketed under United. The arrangement will provide coordinated schedules, convenient connections, participation in United's Mileage Plus program and advance seat selection on United flights for Presidential's passengers, said John R. Zeeman, executive vice president for marketing and planning for United.

For all practical purposes, Presidential's banner will disappear, although the company will remain independent. Its identity will be merged into United's as it was into Continental's for most of last year.

Presidential eventually will displace another regional carrier, Air Wisconsin, which has provided feeder service to United at Dulles. Air Wisconsin will concentrate its activities at Chicago's O'Hare Airport, Zeeman said.

The agreement with United gives Presidential "what every regional carrier wants -- to be the primary feeder, and eventually the sole feeder, for a major carrier who dominates a hub," said Paul P. Karos, an airline industry analyst with L.F. Rothschild & Co. "That's what they really have now at Dulles with United."

United also announced yesterday that it has filed with the Department of Transportation for approval of daily scheduled service between Dulles and Bermuda beginning May 1. The airline will also offer nonstop service from Dulles to Seattle, Zeeman said.