THE AUTHORITY THAT controls publicly owned Dulles International and Reagan National airports has justly come under fire in recent weeks for the spending habits of some of its board members. Few if any of them have splurged so extravagantly as Dennis L. Martire, who single-handedly spent more than $38,000 attending five conferences in 2010 and 2011, according to the agency’s records.

Mr. Martire, an official with the Laborers’ International Union of North America who has served on the airports authority board since 2009, has treated the authority as a sort of high-end travel agency. In May last year, for instance, he took a nine-day trip to attend a 36-hour conference on the Italian island of Sardinia, best known as the Mediterranean haunt of supermodels and Russian billionaires. He brought along a companion, as he did on previous trips to conferences in Prague and Belgium; the authority did not pay the companion’s expenses.

The comportment of board members of the Metropolitan Washington Airports Authority matters because the authority itself matters. In addition to overseeing the airports, it runs the Dulles Toll Road and, critically, the $6 billion Silver Line project to extend Metrorail to Dulles airport. Any whiff of profligacy or ethical fudging — and there’s been more than a whiff — subverts the board’s standing at a critical juncture of the construction of the Silver Line, one of the nation’s biggest infrastructure ventures.

Mr. Martire’s ostensible purpose in Sardinia was to take part in a forum, at a luxurious seaside resort, that was sponsored by the Airports Council International, an industry group. However, the forum’s focus — small regional airports in Europe — was a tangential topic for U.S. airports, to put it mildly. Of the 160 or so delegates who registered for the event, he was almost the only American, according to conference organizers. And no wonder: The forum was irrelevant to U.S. airport executives.

On returning from his Sardinian adventure, Mr. Martire filed an expense claim for $10,586, most of it for a business-class air ticket. (Despite travel guidelines urging frugality, most board members seem to fly business class routinely.) He also wrote a brief trip report, noting that smartphones can be useful tools for airports to communicate with passengers.

In a statement, Mr. Martire defended the trip as “directly relevant to my duties as a Board member” and “fully legitimate and absolutely consistent with [airports authority] policies.” However, he did not explain how it was relevant or answer any of our specific questions — for instance, why he chose to attend a conference in Sardinia when the same sponsor holds almost 20 conferences and seminars in the United States and Canada each year.

Mr. Martire, who was appointed to the airports board by then-Virginia Gov. Timothy M. Kaine (D), is not the only big spender on the airports board. Some other members, though not all, have indulged a taste for expensive wine, fancy meals and conferences in charming venues, all at the authority’s expense. Last year, under pressure, the board reluctantly shelved plans to spend $7.2 million on a three-story addition to its headquarters at National Airport and to double the size of its boardroom, along with adding a $350,000 multimedia system.

Nonetheless, Mr. Martire’s travel constitutes a particularly glaring abuse and is regarded as such by some of his fellow board members. In response to our questions, the airports authority board chairman, Michael Curto, announced Thursday that he has suspended most international travel by board members and established an internal mechanism to ensure compliance with the authority’s policies.

These sorts of sideshows are the last thing the authority needs. It is already under fire for the cost of the 23-mile Silver Line, whose first half is nearing completion; the future of the second phase, extending to Dulles, hangs in the balance. Questions have also been raised about the authority’s procedures for awarding contracts.

Mr. Martire, in particular, has attracted the ire of pro-business Virginia officials for pushing a labor-friendly contracting agreement for the project’s remaining construction. Given that his full-time job is with a labor union, that bit of advocacy had all the signs of a conflict of interest, no matter what legal fig leaf he may have deployed.

The good news is that, in the last year or so, the authority appears to have been getting the message that bad habits have to change. Spending on board members’ travel to conferences, such as Mr. Martire’s junket in Sardinia, has plummeted, and the authority says it is tightening its ethics code, travel policy and transparency rules. Better late than never.

Mr. Curto, the board chair, has also ordered a thorough review of airports policies covering hiring and awarding contracts to former board members and employees, as well as no-bid contracts. That action follows a report in the Washington Examiner detailing a $42,000 consulting contract awarded to former airports board member Leonard Manning, whose term expired last year, to develop Dulles as a cargo hub for flowers shipped from Ethiopia.

Real responsibility for cleaning up the authority rests with board members themselves, who have accepted appointment to a public body that exercises enormous influence. The fact that they are not paid for their board service does not entitle them to lavish trips, meals and perks at public expense. If they don’t care for the arrangement, they are free to resign. In extreme cases, they may also be removed from the board for cause.