Records from the Federal Aviation Administration showed Stephon Duncan, the man arrested after causing a Delta flight to make an emergency landing in Oklahoma City, is a certified flight attendant.
A passenger on that flight said that makes the incident even worse because Duncan had the ability to open the aircraft's door.
"When the guy was in front and tried to open the plane door that was truly the scariest moment of my life, because if he was able to open the door, we would have crashed into the ground," said passenger Brannon Nazarian.
Nazarian is one of dozens of people who were on board Delta flight 1730.
The plane made an emergency landing in Oklahoma City halfway through a flight from Los Angeles to Atlanta.
News 9 obtained the conversation between air traffic controllers and the pilots, while the flight crew attempted to get Duncan under control.
"Delta 1730 can you confirm level 4?" was heard from an air traffic controller to the pilots.
That's the second highest threat level. The call came in as police said Duncan fought flight crew members and other passengers as he tried to open the cabin door.
Nazarian said he and other passengers began noticing odd behavior before the plane took off.
"I remember noticing him wondering, because he boarded the plane with a helmet on," Nazarian said. "Everyone remembered that he put a black bag in every single different bin in the first-class cabin."
Reports said the suspect also hid items around the plane, like tennis balls with words written on them, food, and trash.
Witnesses told police Duncan began drawing even more attention while the plane was in the air. Duncan reportedly told the flight crew a terrorist was on board and in the seat next to him.
Nazarian said he got an eerie warning from Duncan right before the chaos ensued.
"He was still in the aisle way talking to a flight attendant and he like nudges me on the back and goes, ‘You need to go take your seat right now,’" he said.
Nazarian said then a voice came over the loudspeaker.
"Which I later found was him [Duncan] and he told us that we need to grab oxygen masks," he said. "Next thing I know I see him screaming in the aisleway at the flight attendants and push comes to shove and I hear a loud slam at the front of the airplane, and I see a flight attendant shoved against the wall."
Pilots called for any large men on board to help the crew restrain Duncan.
"Delta 1730 they're asking me to see if the passenger was subdued or anything like that," said air traffic control.
"[The] Captain is talking to the back right now. We do believe that they are subdued, and they are in the flex cuffs," one of the pilots said back.
Police searched Duncan's bags after landing but didn't find anything. He is facing an assault charge.