A Florida man accused of assaulting a flight attendant on a Delta Air Lines flight from Seattle to Beijing was expected to appear in federal court on Friday, authorities said.

Airport officials said the incident was not thought to be a national security threat.

The U.S. Attorney's Office in Seattle identified the man as Joseph Daniel Hudek IV, of Tampa. It was not immediately clear if he had a lawyer.

He was in the first-class section of the plane when he attacked the flight attendant about 45 minutes into the flight, officials and witnesses said.

The flight attendant and another passenger from Delta Flight 129 were transported to Highline Hospital for treatment of non-life threatening injuries, said Perry Cooper, a spokesman for Seattle-Tacoma International Airport.

Ayn Dietrich, an FBI spokeswoman, said the investigation was ongoing and more details would be provided in court.

After the attack started, passengers helped restrain the man until the plane landed back at Sea-Tac, and Port of Seattle police arrested the man, Cooper said.

"The passenger was restrained on board and was removed from the flight by law enforcement without further incident," Delta said in a statement.

Passenger Dustin Jones was seated just behind the curtains that lead to first class, and said he could tell there was a scuffle happening.

"One of the flight attendants ran back and said there was a Code 3," Jones told KIRO-TV. "There was a serious fight up front."

Jones said he saw the man handcuffed and zip-tied being rolled into the terminal in a wheelchair after the plane landed.

"He started yelling for help," Jones said. "And so he turned the wheelchair over in the middle of the airport, screaming for people to help him, just being belligerent."

The FBI and the Port of Seattle Police interviewed passengers. The flight left for Beijing later Thursday night.