A customer on a WestJet flight from Toronto to Edmonton says there were some tense moments as he and others helped the crew subdue an unruly passenger.

Steven Kelley told CTV Edmonton he was sitting four rows back from the cockpit of the Boeing 737 when a man wearing a backpack twice walked from the back of the plane to the front during the last half of the four-hour flight.

Kelly says the man approached the flight attendant each time and asked to get off the plane while it was still in the air.

RCMP said Wednesday that a 20-year-old man was arrested after causing a disturbance on a flight.

The individual was taken into custody without incident once the plane landed.

Police are investigating but so far no charges have been laid.

"When he came up the second time, I knew right away that there was something, that something was going to happen," Kelly said.

He said the flight attendant asked for help so he and some other passengers stepped in and helped restrain the passenger.

'We ziptied him'

"Jumped up, grabbed the guy, basically got control of one arm and maybe his neck," recalled Kelly. "We ziptied him, and they brought him to the back of the plane where they held him for about a half hour or so until we landed."

According to Kelly, another passenger said the man had spent the first three hours of the flight praying, but it wasn't clear exactly what his motivation was. He also said "it was weird" the man was wearing a backpack three hours into the flight.

"The entire time he was calling us 'non-believers' and saying if there were any believers on board, to kill him," Kelly said.

"I don't honestly know if he was trying to open the door, he definitely was moving towards the door, he was only a few feet away from it."

WestJet declined comment except to confirm an incident took place on board a flight "involving an unruly individual who was removed by RCMP at the request of the crew."

Earlier this week there was an incident on an Alaska Airlines flight where an agitated passenger tried to open a rear door during the flight. The plane, which was en route from New York City to Seattle, was diverted to Minneapolis.