United Flight 116 from Hong Kong landed around 1:40 p.m. at Newark Liberty Airport.
The suspect was removed from the plane about 20 minutes later. He was wearing a blue jacket and a hood.
The FBI had said earlier that the man claimed everyone aboard was being poisoned but the agency now says it's working to clarify what the man said.
Jacques Roizen, one of the passengers who restrained the man responsible for the incident, told ABC News that around 10 hours into the 16 hour flight,the suspect started screaming.
Roizen said that the man claimed he was poisoned, had secrets from the CIA and mentioned Edward Snowden's name a number of times. Roizen said he did not believe the man ever said he poisoned people on the plane.
Another passenger, Peter Jones of Washington, says he heard the man claim he himself was going to be poisoned.
Roizen says the man was frightened for his own safety, thought people were after him and that he needed to be arrested. Four to 5 passengers restrained the man, he said.
Then, the crew gave the passengers plastic handcuffs and the whole incident was resolved within 10 minutes. Roizen and another person, sat next to the unruly passenger for the remaining 6 hours of the flight calming him down by talking about their families, Father's Day and children.
A United Airlines spokeswoman says the crew followed procedures and the flight continued as scheduled.
The FBI said the man was hospitalized after being removed from the plane, but did not provide further information about him.
Passengers began leaving the terminal after interviews conducted by the FBI and PAPD detectives.