Braniff International inaugurated the first domestic air service aboard the Concorde yesterday between Washington and Dallas-Ft. Worth.

The Concorde flights will link Paris and London to DFW with a stop in Washington, enabling travelers to save at least an hour from the fastest air service now available between the Southwest and Europe.

Domestic flights of the European supersonic plane were made possible by a first-of-its-kind interchange agreement involving a U.S. airline and foreign carriers.

Under the agreement, title to the planes will be transferred during the Washington stop from Air France and British Airways to a new American subsidiary they have set up, which in turn will lease the aircraft to Braniff for its domestic services. Title then will be transferred back on the return trips from Dallas.

Braniff pilots fly the 100-passenger plane at subsonic speed -- about 100 miles an hour faster than conventional jets -- between Washington and DFW, pilots for British Airways fly the London-Washington flights and Air France pilots fly the Paris-Washington segments at twice the speed of sound, about 1,350 mph.

Braniff will operate Concorde flights to and from DFW five times a week; the fare is $15 more than normal first-class fares.

Top officials of the three airlines participated in ceremonies yesterday at Dulles International Airport after arriving on Air France and British Airways Concordes almost simultaneously. After the ceremonies -- when title to the planes was passed -- they boarded the planes again to take off to DFW, where a "Texas-style" welcoming ceremoney was planned for the two planes which were scheduled to arrive simultaneously.

Before flying, the numbers of the planes had to be changed to conform to the U.S. system -- a project in which some sticky white paper was slapped on top of the first letter of the plane's number.

"The Concorde represents the world's greatest technology in commercial aviation today," Braniff Chairman Harding L. Lawrence said during the ceremonies. "We are proud to be the airline which will make Dallas-Ft. Worth the first supersonic gateway in the interior of the United States."

Lawrence hopes to be able to work out other interchange agreements allowing Braniff to carry passengers aboard the Concorde to South America from New York.

According to the airline executives, the interchange agreement has no time limits. "It's just like a marriage," Jean-Claude Martin, senior vice president of Air France, said. "It lasts as long as the two want it."