John “Jack” E. Potter’s appointment to lead two of the Washington area’s busiest airports and the construction of a Metrorail extension to Dulles International Airport closed out a year-long — and, at times, rocky — search for a chief executive to the Metropolitan Washington Airports Authority.

The selection of Potter, a former U.S. postmaster general, is expected to bring stability to the airports authority and allow it to train its attention to managing the multibillion-dollar Metro project.

After the board’s formal vote Wednesday, former congressman Tom Davis (R-Va.), the vice chairman, called Potter a “first-class professional and outstanding leader” who would “bring a lot of credibility to this organization.”

The airports authority has been battered with criticism and come under increasing scrutiny from local, state and federal officials for the rising cost of the second phase of the Metro project to Dulles and other parts of Loudoun County. The inspector general for the Department of Transportation announced this week that his office would investigate the authority to “ensure accountability and transparency.”

Early in the year, the board was also criticized for its search for a new leader to replace James E. Bennett, who announced his retirement in April 2010. The 13-member board — which includes appointments from the president, the governors of Virginia and Maryland and the D.C. mayor — scrapped its initial search after becoming bitterly divided over another front-runner, Nathaniel P. Ford, the outgoing head of San Francisco’s transit agency.

John E. “Jack” Potter said he is committed to “world-class” airports and rail and ending budget debates over the airport Metro station. (Andrew Harrer/BLOOMBERG)

Board chairman Charles D. Snelling declared the renewed search that resulted in Potter’s hiring Wednesday a “process of healing and reuniting of the board. We’re in a good place.”

But there were still signs of tension in the board’s 11 to 2 vote. The two board members who voted against Potter — Shirley Robinson Hall of the District and Richard “Dickie” S. Carter of Maryland — said they favored other candidates with airport management experience. Warner H. Session of the District, who led the search, also expressed disappointment but threw his support behind Potter, saying, “What we really need now is leadership.”

Potter, 55, retired in December after a 32-year career with the Postal Service, one of the nation’s largest employers. He won the admiration of rank-and-file employees even as he reduced the size of the workforce. Potter’s proposals to eliminate Saturday delivery and close thousands of post offices, however, went nowhere on Capitol Hill, and the Postal Service has continued to lose billions of dollars a year with declining mail volume.

In response to concerns about his lack of aviation experience, Potter said he oversaw more than $2 billion in air shipping business at the Postal Service, making him “very familiar” with aviation. He accepted the job, he said, because the authority “can do more to grow the economy of this region than almost any other organization.”

According to Potter’s five-year contract, he will receive a salary of $350,000, plus a $25,000 signing bonus and annual bonuses of up to 20 percent of salary. His new salary is comparable to that of Richard Sarles, the chief executive of the Washington Metropolitan Area Transit Authority. Potter was paid $276,840 a year as postmaster general.

Potter said he is committed to “world-class airports and world-class rail” and to bringing “closure” to debate over the planned airport Metro station. Elected officials in Northern Virginia have urged the board to reverse its vote in favor of an underground station and to get behind a less expensive aboveground location.

Board members are immersed in negotiations with elected officials to try to trim the $3.5 billion price tag for the second phase of the rail project. Transportation Secretary Ray LaHood, who is refereeing the talks, has asked the players to try to resolve their differences by the end of the month.

Potter, a Potomac resident, told reporters that he would not stake out a position until he is fully briefed.