Leading historians, scientists and environmentalists are calling on Gov. Maura Healey to stop the expansion of private jet service at Hanscom Field in Bedford.

Hanscom Field airport is at the intersection of Lexington, Bedford, Concord and Lincoln. The proposed expansion would add more than half a million square feet of luxury jet hangar space and double the current private jet infrastructure, according to plans for the project.

Opponents of the proposal, including descendants of Concord luminaries Ralph Waldo Emerson and Henry David Thoreau, delivered a petition and letter against Massport’s expansion plan to the governor on Tuesday.

Anna West Winter is with the group Save Our Heritage, a nonprofit dedicated to preserving and promoting historical, cultural and environmental resources in the towns surrounding Hanscom Field. She says the plan could mean more than 6,000 additional flights at Hanscom each year.

“The proposed facility of 522,000 square feet, the equivalent of 38 football fields, will generate approximately 6,000 additional jet flights annually,” Winter said in her remarks at a State House news conference. “These planes will be flying directly over and significantly impacting the abutting Minuteman National Historical Park, including the homes of Emerson and Thoreau, and numerous additional nearby sites on the National Register of Historic Places.”

The private jet expansion site lies near Henry David Thoreau’s Walden Pond and Walden Woods, revered as the birthplace of the environmental movement and for Thoreau’s prominent role in furthering the ideals of equality, social reform and protecting vulnerable natural resources.

Opponents also say the project will negatively impact the climate through increased greenhouse gas emissions.

Mark Thoreau, a family descendant of the iconic writer, addressed that concern in his remarks at the State House.

“I believe Henry would direct our attention to changing the perspective and intentions of those who would, for personal profit, act to disproportionally hasten the cataclysmic warming of our planet, like the proponents of this misguided and harmful Hanscom private jet development project,” he said. “There is absolutely no rational excuse for annually adding 6,000 private jet flights over the endangered historic site.”

Wide shot of a room filled with people sitting and listening to a woman speak at podium during a news conference.
A news conference was held inside the Massachusetts Senate reading room before several groups opposing a Hanscom Airfield airport project delivered a letter and petition to the governor.
Robert Goulston GBH News

According to a federal environmental impact study conducted by the Federal Aviation Administration, the purpose of the project is to meet the increased demand for private flights. The federal government study concluded the expansion would not significantly affect the quality of the human environment.

The project is also being reviewed by the Massachusetts Environmental Policy Act Office, which reviews proposed development projects for their environmental impacts and how they can be addressed. In June, MEPA rejected the draft environmental impact report because it did not adequately address the potential impacts of the project. Their office has requested a better analysis.

Kathi Anderson is the executive director of the Walden Woods Project, one of the sponsoring organizations of the petition to stop the project. She told GBH News their biggest concern is increased jet traffic.

“Particularly because of noise and the impacts of incoming and departing jet aircraft over Walden Pond,” she explained. “It’s very disruptive to visitors, and especially in terms of outside presentations. We have a lot of education programs that we run, and you just can’t hear when jets fly over.”

Winter said the petition compiled by the National Trust for Historic Preservation was signed by more 4,000 people nationwide.

“We want the governor to understand that we support her efforts to halt this project. And we feel that she has an important role to play,” Winter said.

Hanscom is owned and operated by Massport. The Healey administration tells GBH News it continues to monitor the MEPA process, and the project remains on hold for now. Opponents want Healey to take it off the table for good.