Labor official Dennis Martire said Tuesday that Virginia Gov. Robert F. McDonnell’s campaign to oust him from the board of the Metropolitan Washington Airports Authority was “pure politics at play.”

On the eve of his departure from the board charged with overseeing construction of the $5.6 billion Dulles Rail project, Martire said he had mixed feelings about his tenure, but no regrets. “We became a political punching bag,” he said of the airports board.

For months, Martire was involved in a costly legal battle after McDonnell (R) sought to remove him from the board. Last month, Martire returned to his seat on the dais. Then minutes later, as part of a confidential settlement, he announced he would step down after this month’s meeting, which is Wednesday.

Wednesday’s board meeting is the first gathering since the D.C. Council approved legislation to expand the MWAA board from 13 to 17 members. Four new board members — two from Virginia and one each from the District and Maryland — are expected to take their seats Wednesday. They are Barbara Lang of the District, who is president of the D.C. Chamber of Commerce; Earl Adams Jr. of Maryland, who is a lawyer with DLA Piper; and Caren Merrick, a businesswoman, and Lynn Chapman, both of Virginia.

In addition to welcoming new board members, the board is expected to appoint a new ethics officer and to receive updates about the Dulles Rail project, including a list of contractors that may be selected to build Phase 2.

Martire, who was appointed by McDonnell’s predecessor, Timothy M. Kaine (D), and will step down at the conclusion of the meeting, said that as a union official, he brought an important perspective to a board dominated by lawyers and former elected officials. Martire is vice president and Mid-Atlantic regional manager of the Laborers’ International Union of North America. But Martire’s labor credentials clashed with McDonnell’s policies.

Martire said elected officials, including McDonnell, Rep. Frank R. Wolf (R-Va.) and U.S. Transportation Secretary Ray LaHood, have unnecessarily politicized a board that was created to be insulated from state and federal interference. In addition to managing the Silver Line rail project, the board oversees Dulles International and Reagan National airports and the Dulles Toll Road.

But some would say the board created its own problems.

During his tenure, Martire came under fire for what some, including a federal inspector general, saw as questionable travel expenses, including trips to Sardinia and Prague. The authority was also faulted for awarding no-bid contracts to former board members and for hiring one former board member, Mame Reiley, to a $180,000-a-year job the day after she stepped down. Many board members said they were unaware that Reiley had been hired to work at the authority. Last month, she was let go from her job.

Martire defended his travel expenses as a necessary part of his work as a board member. He said the trips were in keeping with MWAA policy.