By Yaron Steinbuch

A United Airlines flight from New Jersey to Vermont sparked a massive emergency response Sunday after a disturbing note was found inside a bathroom.

Flight 3613 took off from Newark Airport at 3:14 p.m. with 65 passengers for a flight to Burlington International Airport, but 20 minutes before landing, the pilot was notified of a threat, WPTZ reported.

Authorities have not described the nature of the threat but a passenger on the flight told the outlet that “someone left a note.”

The pilot notified air-traffic control and a massive emergency response was launched at the airport, which was closed for several hours after the plane landed about 4:30 p.m. and was taken to an isolated spot on the tarmac.

Responding agencies included the Vermont State Police Bomb Squad, local police, the Department of Homeland Security and the FBI.

Passengers told WPTZ that they were given limited information as they sat on the plane for about two hours before being allowed to get off.

K-9 units were brought aboard around 6:30 p.m. to sweep the cabin, the travelers said.

Once the plane was cleared, they were allowed to leave the aircraft, but without any of their belongings.

One of the 65 people on board was Vermont State Senator Phil Baruth.

“They sniffed up and down the plane and then they sniffed each passenger,” Baruth told WCAX.

“They isolated us with police at both ends and they don’t know whether one of us could be a bad actor so that doesn’t feel great.”

Baruth told WPTZ that the frightening incident was sparked after “someone left a note.”

“It feels unfair on one hand that someone left a note and ruined everyone’s day. Obviously someone a little deranged,” he said.

“On the other hand, authorities here handled everything perfectly and at no time did I feel unsafe.”

Another passenger, Melissa Jones, told WPTZ: “It was scary. I had to stay calm because of my kids.”

Authorities said no credible threat was discovered and no one has been arrested, though the investigation remains ongoing.

“What we have here is a safe group of people. We have a safe plane. We have a safe airport. We have procedures that were followed and we have a successful outcome,” acting Burlington Police Chief Jon Murad said.

The Post has reached out to United for comment.