Brian Plummer was sitting behind a Delta Air Lines flight preparing to leave La Guardia airport on Monday when, he said, he noticed a man and a woman with a large service dog nearby.
The plane bound for Atlanta was not completely full, Mr. Plummer said, and the couple changed seats several times.
The man and woman never settled in, and as Flight 462 began heading for a runway, the man stood up, ignoring a flight attendant’s order to stay, saying he had post-traumatic stress disorder, Mr. Plummer.
Soon, Mr. Plummer said, he felt the plane shake. It was not immediately clear why, but the flight crew finally told the passengers what had happened.
The man forced open a cabin door, activating an emergency slide, and then he, his female companion and their dog slipped from the plane, officials said.
The couple was in custody; it was not clear what taxes, if any, could be faced or whether it could be banned from flying Delta in the future.
It wasn’t the first time a panicked passenger had made such a maneuver at a New York airport, but neither Delta, the FAA, nor the New York and New Jersey Port Authority, which operates La Guardia, could say Monday how unusual it was for someone to make such an escape.
“This does not happen every day at the airport,” said Lenis Valens, a spokeswoman for the authority.
Mr Plummer said he noticed the man sitting after the plane left the gate. “They looked very nice,” Mr. Plummer said of the couple.
The man told a flight attendant that he could not sit down because of his post-traumatic stress disorder, Mr Plummer said.
“If I sit down, it’ll scare me,” the man said, Mr. Plummer recalled.
The flight attendant again asked the man to sit down and refused again, Mr Plummer said. Instead, he began to walk to the front of the plane, far enough that Mr. Plummer lost sight of him.
The plane, which was scheduled to depart shortly before 10 a.m., returned to the gate, where the remaining passengers “took off normally and were accommodated on alternate flights,” a Delta spokeswoman said. (Mr. Plummer said his departure was delayed by several hours.)
No one was injured in the incident, authorities said. It was not immediately clear where the service dog was.
The most famous example of an unauthorized slip exit took place 10 years ago at Kennedy International Airport, with a JetBlue flight attendant who said he was involved in a dispute with a passenger.
In this case, after announcing her intentions regarding the sound system of the plane, the flight attendant activated an emergency slip, slipped down on the asphalt and threw her tie on the ground while leaving.
More recently, a passenger aboard a flight to Florida at Newark Liberty International Airport fled through an emergency exit and landed on an inflatable slide while the plane was still at the gate in February 2018, according to WNBC.
When officers arrived to arrest him, the man shouted that he did not belong to the plane because it was not his flight, the television station reported.