Airlines providing regional service between the Vineyard and Logan International Airport could receive relief from proposed hikes in landing and takeoff fees under a plan submitted by the Massachusetts Port Authority to federal regulators earlier this month.

The exemption program is one element of Massport's peak pricing proposal, which would raise landing fees at the Boston airport during peak hours to $150 per landing and departure.

Vineyard airport manager Bill Weibrecht and Cape Air communications director Michelle Haynes both said this week they are cautiously optimistic that the exemption program would minimize the impact of any fee hikes on regional air service.

"In the end Massport addressed the large majority of our concerns - that year-round service is able to continue, and that the number of exemptions be adequate to support preexisting service levels," Mr. Weibrecht said.

"It looks good. It looks like they [Massport] understood the unique niche that air service has here," said Ms. Haynes. "The plan as written does afford some protections and takes into account the unique seasonal conditions of the Cape and Islands."

When Massport first announced its plan to implement peak pricing, Cape Air executives said the massive fees would sink the airline, the Island's main carrier.

Cape Air connects the Island to airports in Boston, Hyannis and Nantucket on a year-round basis and offers hourly flights from the Vineyard during the summer. The regional airline transports about 95,000 passengers a year to and from the Vineyard and employs more than 40 people on the Island.

In his capacity as chairman of CapePorts - a coalition of southeastern Massachusetts airport operators - Mr. Weibrecht took the lead last month in working with Massport officials to find a way to minimize the impact on small communities.

"Air service to the Cape and Islands couldn't have had a better advocate than Bill," Ms. Haynes said. "He hit the ground running, he was tenacious and he did truly a formidable job."

Massport's peak pricing proposal is part of a mandated report to the Federal Aviation Administration (FAA) detailing management plans to build a sixth runway and alleviate flight delays caused by excessive northwest winds. Massport filed the report to the FAA May 5.

In it, state officials included a program through which certain small communities can qualify for exemptions from the fee hikes based on their status as Essential Air Service (EAS) communities or as special circumstances communities.

EAS is a federal designation based on certain air service conditions that were in effect in 1978. The Vineyard, Nantucket and Hyannis already have been granted EAS status.

EAS communities would be granted a specific number of exemptions - that is, flights that could land or depart during peak periods without incurring the additional surcharge. The number of exemptions would be tailored to each community's needs, and based on the number of flights between that community and Boston during August 2003.

For the Vineyard, that means 13 operations - either an arrival or a departure - would be exempt from the surcharge each day during peak periods.

Operations in excess of that number would be subject to a $150 fee.

The peak periods would be forecast at least six months in advance, based on simulations using published airline schedules. The new fees would be imposed only when an average of 15-minute delays are projected for all flights over a period of at least three consecutive hours.

An advance warning would be issued to allow airlines to jigger voluntarily with schedules. After tracking any schedule changes, Massport would issue a final notification as to whether fees would be imposed at least a month in advance.

Mr. Weibrecht said peak periods likely would occur between June and September, between the hours of 4 and 8 p.m.

The FAA will review Massport's demand management program for several months before either rejecting it, recommending changes or approving it as is.

"We're still awaiting our 20 questions, but we feel good to have played our role," said Mr. Weibrecht.