When a violent fist fight broke out between two passengers aboard an international flight from Japan to Los Angeles this week, cinematographer Corey Hour of Phoenix was sitting just a few rows back.

“The gentleman in the red was provoking everyone around him. He had some type of issue with people and I believe the gentleman in the black shirt was minding his own business and he got caught up in everything,” Hour told 12 News.

Using his cell phone, Hour captured video of the two men punching each other on the flight, run by Japanese carrier All Nippon..

That video that has since gone viral.

Hour says he didn't realize how quickly things would escalate until after he started recording what he describes as an unruly passenger.

“He (the alleged unruly passenger) was going back and forth attacking anyone in his vicinity, verbally and physically,” Hour said.

Hour eventually had to confront the man himself and that’s when other passengers also stepped in to help get the alleged unruly passenger off the plane.

Flight attendants managed to remove the man from the plane.

That was when law enforcement got involved with the incident -- but until then it was just passengers and airline employees.

While most people know U.S. Air Marshals can be found on several thousand flights any given day, that’s just a small percentage of the planes taking off every day.

“The FBI has an agent assigned to major airports because crime aboard aircrafts happens on a regular basis,” said retired FBI agent John Iannarelli.

And Iannarelli says in cases like this where there are no weapons or a serious threat to national security, the marshal may not want to risk getting involved.

“Their job is to protect the flight against terrorism and they're not going to give up their position and let people know on board, because this could be a diversion for a terrorist that wants to commit an act,” he said.

He says in order to protect themselves, passengers should always be aware and if they notice any strange activity or someone acting erratically, they should immediately notify authorities or an airlines employee.

The goal is to confront the problem before the plane takes off.

“The passenger can be pulled aside and questioned beforehand,” Iannarelli said, “if they're deemed to be a problem they're not going to be allowed on board.”

The alleged unruly passenger was only described as a 44-year-old American.

According to Japanese news reports, after leaving the plane he allegedly choked an airline employee before being arrested.

Those same reports say Japanese authorities believe the man was intoxicated.