James H. Burnley IV, who overcame clashes with several senators by promising to hire more air traffic controllers and not force new efforts to sell Amtrak, was confirmed yesterday by the Senate as President Reagan's third transportation secretary.

The 74-to-0 vote came after Burnley spent several weeks appeasing senators who objected to his blunt style and outspoken defense of transportation policies unpopular in Congress.

The Senate also confirmed, by voice vote, Mimi Weyforth Dawson as Burnley's deputy. She is a member of the Federal Trade Commission.

They will take over the department at a time of public concern over air safety. There have been two major airline crashes in four months and two commuter crashes in the last three weeks. Last month, two congressional committees held hearings on airline maintenance.

Burnley, 39, is the youngest secretary in the department's 20-year history and the first deputy secretary to ascend to the $99,500-a-year job. He has overseen the department's day-to-day operations since he was made deputy secretary in 1983. He joined the department in 1982 as general counsel.

He succeeds Elizabeth Hanford Dole, who resigned in September to join the presidential campaign of her husband, Sen. Robert J. Dole (R-Kan.)

Burnley said he was pleased to have been confirmed and looks forward to continuing "this administration's commitment to a safe, efficient transportation system."

In remarks on the floor, several senators praised Burnley's professional qualifications, but made a point of voicing their ambivalence toward him.

"Mr. Burnley has been part of the management over at DOT that has been slow to recognize the obvious problems we face, and even slower to act toward solving them," said Sen. Ernest F. Hollings (D-S.C.), chairman of the Commerce, Science and Transportation Committee.

Hollings, who has held a series of hearings to consider re-regulation of the airline industry, said the state of the country's airlines requires the new secretary to play more than a "caretaker's role" in the final 13 months of the Reagan administration.

Sen. Frank R. Lautenberg (D-N.J.), who chairs the Appropriations subcommittee that handles the Transportation Department's budget, noted that the agency has been slow to hire air traffic controllers and slower to recognize poor morale in the controller ranks. "Worse," he said, "DOT has not been forthright in discussing these issues."

Referring to Burnley's peacemaking efforts, Lautenberg said: "Mr. Burnley, at times, has had difficulty working constructively with members of Congress. But, we've seen a change."

Sen. John C. Danforth (R-Mo.) said Burnley was the best choice for the job "under the circumstances," adding that it is important that the new secretary pick up the job without a long break-in period.

Burnley's troubles with Congress date from last May, when Burnley and Lautenberg clashed on CBS News' "Face the Nation." Burnley implied Lautenberg was speaking "gibberish and nonsense," about air safety; Lautenberg took offense.

After Burnley's nomination Oct. 8, Lautenberg met with Burnley to discuss transportation issues, such as Amtrak, and extracted a written apology and promises on several issues, including Amtrak, highway funding, and hiring of air-traffic controllers.