By IVAN PEREIRA and ALEX STONE, ABC News

(LAS VEGAS) — It wasn’t a bird or another plane that grounded a flight from Las Vegas to Portland, Oregon, before takeoff Saturday, but rather a man who got onto the wing, according to police and an eyewitness.

Police arrested Alejandro Carlson, 41, after the man reportedly got onto the tarmac at McCarran International Airport, ran up to an Alaska Airlines airplane and somehow climbed up one of the wings, the Las Vegas Metropolitan Police Department said. The suspect moved about the wing for nearly 45 minutes before he fell onto the tarmac, Erin Evans, a passenger on the plane, told ABC News.

“It was definitely one of the strangest things I’ve ever seen in my life,” Evans, 50, of Vancouver, Washington, said.

The incident took place around 1:30 p.m. local time while the plane was taxiing for takeoff, according to Evans and police. The LVMPD said it appeared the man jumped the airport’s fence.

Alaska Airlines said in a statement that the plane’s pilots noticed a man running to the aircraft and immediately called the air traffic control tower for help.

Evans, who filmed the incident and posted it on her Facebook page, said she could not see how the suspect was able to make his way to the top of the wing, but within minutes he was outside her window, walking on it.

“Our first reaction was, ‘Uhhh, who is this guy? Is this a terrorist type of activity?"” Evans said.

Air marshals inside the plane instructed passengers to remain in their seats as they and officers tried to get the man off the wing, according to Evans. After about 45 minutes, officers used emergency exits to get onto the wing and approached the suspect, according to Evans’ video.

The man walked toward the very edge of the wing, slid off and fell onto the tarmac, and officers quickly apprehended him, the video showed.

Evans said she and the other passengers watched the incident in shock.

“The flight attendant told me in the 30 years that she’s been a flight attendant nothing like this happened before,” Evans told ABC News.

The Federal Bureau of Investigation responded to the airport security breach, but it was quickly determined the incident was not a federal case, and LVMPD took custody of Carlson, according to investigators. He was treated for minor injuries at University Medical Center and booked into the Clark County Jail for trespassing and disregard for public safety, police said.

The investigation is ongoing, according to police.

Evans commended the plane’s crew, airport officials and police for their handling of the situation.

“Everyone was relieved in the end,” she said.

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