William J. Weibrecht, the manager of the Martha's Vineyard Airport for the last five years, stunned members of the Dukes County commission and airport commission this week when he announced his intention to quit the job, effective May 20.

In his letter of resignation, hand-delivered to commissioners at their regular meeting Wednesday night, Mr. Weibrecht pointedly cited his ongoing legal dispute with the county commission over salary.

"The county's decision not to abide by its commitments undermined the employment agreements which the airport commission and I negotiated in good faith," he wrote in the letter dated April 20.

Mr. Weibrecht told the Gazette yesterday he had already accepted another job in the private sector with an aircraft services company based in New England and Florida. He declined to specify the name of the firm.

"I've appreciated everybody's support," he said. "The airport is huge asset to the Island."

On Wednesday night county commissioners voted to appoint assistant airport manager Sean Flynn acting manager until a permanent replacement is hired. Mr. Flynn is also a litigant in the complicated lawsuit that pits the airport commission against the county commission.

A little more than two years ago, Mr. Weibrecht and Mr. Flynn filed a court complaint after county commissioners refused to pay them the salaries they had negotiated with the airport commission. Instead, the county insisted on paying the managers lower salaries according to a wage scale governing county employees.

Airport commissioners are appointed by members of the Dukes County commission.

The case went to trial in March and now awaits a decision by a superior court judge.

Despite the legal friction, Mr. Weibrecht has been widely praised for improving both the financial condition and the physical infrastructure of the county-owned airport.

"He's been an excellent administrator. It was a total shock at the meeting," said William Mill, of Vineyard Haven, who is in the middle of a second term on the airport commission and one of the backers of the higher salary deal for Mr. Weibrecht.

County manager E. Winn Davis was equally taken aback.

"I was very surprised," Mr. Davis said yesterday morning following the meeting. "I think he has been an effective manager and as I said to him last evening, he will be missed."

But Mr. Davis also stuck to his official position on the question of who has authority to establish salary scales for airport employees.

"I regret that he would make this an issue of his moving on. I think people should move on for good jobs and more valuable jobs and not out of frustration, but I would disagree with his contention that the county didn't live up to its commitments. The county never agreed to make the airport more autonomous — all they agreed to do was never interfere with the airport operation and they haven't. I think the disagreement lies not with the county but with the former airport commission and its hopes and dreams," Mr. Davis said.

John Alley, who is chairman of the county commission, agreed.

"Bill has done an incredible job managing the airport and I am pleased with the growth he has achieved and how he seemed to grow into the job," Mr. Alley said, adding: "While I do not agree with parts of his resignation letter, I wish him and his family all the best in his new position."

Mr. Weibrecht's letter gave a clear indication that he will not abandon his stake in the lawsuit.

"I will continue to prosecute my claims against the airport commission and county," he wrote. "Unfortunately, the primary victims of this process will be the good residents of Dukes County, who will have to foot the bill, not only for the county's substantial legal fees, but also for my own in addition to the award of damages."

At the heart of the lawsuit lies a simple salary dispute: Mr. Weibrecht and Mr. Flynn want the annual salaries they say they negotiated in good faith with the airport commissioners. According to the agreements, Mr. Weibrecht would be paid about $86,000 and Mr. Flynn about $67,000 a year. Instead, the county is paying them according to its wage scale, with Mr. Weibrecht receiving $74,000 and Mr. Flynn $60,000.

The airport commission wants the flexibility, which it says exists in its charge to manage the airport, to offer salaries that will attract and retain qualified managers.

County commissioners consider the airport managers county employees who receive the same health and retirement benefits as other county employees. They do not want the airport commissioners, whom they appoint, to have the ultimate say over how the managers are paid.

Mr. Mill said yesterday that this turf war between the two boards definitely soured the relationship with Mr. Weibrecht.

"He's been given a very hard time by the county," said Mr. Mill, who added that it's now up to a judge to decide the issue of authority.

"It will make a big difference on whether we can offer salaries commensurate with the job," he said.

Mr. Davis said he does not think the lawsuit will be a deterrent in attracting candidates for the airport manager position.

"We're not terribly worried about that," he said.

He said he expects Mr. Flynn will stay on as acting manager through the summer. Mr. Davis said he too may decide to apply for the job.

"Sean is eligible to apply for the position, but if the position is being offered as a county employee, he has to keep that in mind. The best thing we can do for the airport, the county and the applicant is be consistent and come together and not play games with people — as the former airport commission did," Mr. Davis said.

The Vineyard airport employs 12 people on a full-time, year-round basis and hires another eight to ten employees in the summer months.