A proposed expansion at Hanscom Field should not be cleared for takeoff, according to climate activists who were arrested while protesting the development in Bedford.

Massachusetts State Police arrested 20 members of Extinction Rebellion Boston for disrupting flights at the airfield Saturday morning as they “breached a security perimeter and trespassed on the tarmac” to block planes from taxiing to the runway. MSP spokesman David Procopio told the Herald they were charged with trespassing, disorderly conduct and “potentially other related charges.” The scene cleared shortly after the event began around 8:30 a.m.

The activists, who oppose a project that would bring Hanscom 17 additional hangars for private jets due to potential environmental harm, blocked the entrances of Signature Aviation, Jet Aviation, and Atlantic Aviation, until they were arrested, the group said in a release. Others “encircled the wheels of private jets with their arms and refused to move.”

James Comiskey, one of the arrested activists who the Extinction Rebellion says is a Boston-based sustainability professional, called Gov. Maura Healey out for being silent on the proposed project.

“It’s an unjust atrocity that we allow the wealthy to pour greenhouse gasses into our atmosphere just because they can,” Comiskey said in a statement. “The 1% accounts for 50% of all aviation emissions. Governor Healey has not taken a stand on this issue, so we’re here to stop these flights from taking off since she hasn’t done it herself. This expansion, and private jet use in general, must be stopped.”

The project is currently under review by the Massachusetts Port Authority which governs commercial activities at the airfield. Massport has said increased hangar space will allow for more planes to remain at Hanscom between flights instead of being forced to be ferried to other locations for storage, the hyperlocal Concord Bridge reported in February.

A developer behind the proposal looked to add 26 new hangars initially but reduced the number to 17 that would have the same overall capacity — about 495,000 square feet — as the original plans, affecting three fewer acres of land, the Bridge reported. The proponent added that the project could decrease daily flights by around nine per day, according to the outlet.

Massport, in response to a Herald request for comment, provided information on the protest but declined to explain why the project is needed.

Researchers at Tufts University recently identified ultrafine particles in Bedford neighborhoods that may be connected to aircraft operations at Hanscom but the health implications are uncertain, the hyperlocal Bedford Citizen reported last week.

Residents of Bedford, Concord, Lexington and Lincoln — towns where Hanscom is sandwiched between — have led a petition that has been signed by over 10,000 Bay State residents. State Sen. Michael Barrett has also been a vocal critic of the expansion.

“In seriously entertaining a proposal to build multiple new hangars for super-polluting private jets at Hanscom Airfield, Massport is on the verge of a stomach-turning two-fer: aiding and abetting the warming of the planet and pandering to the concentration of private wealth. You can’t do much worse than that, right?” Barrett said during a protest at the State House last October.

Climate activists are up in arms about the potential harm that such a project could lead to, saying the expansion “would accommodate a 300% increase in private jet services” and is meant for the “wealthiest travelers in the region, many of whom frequently take short-hop flights to recreational and luxury destinations.”

“I think most people don’t know that on average, per passenger, private jets contribute 10 times more carbon pollution than commercial airlines,” activist Harley Takagi Kaner said in a statement. “These flights are only available to the ultra-rich—who, by the way, receive a tax exemption on aircraft—and we’ve seen them utilize this luxury to take jaw-droppingly unnecessary 30-minute flights.”