Cellphone videos show the man, wearing what looks like khaki-colored sweatpants and a fanny pack, shimmying along the wing as bemused passengers stare out the window.
At one point, he rolls his pant legs up, appears to throw his shoes at the officers, and then tries to climb even higher. A group of officers walks out on the wing, but before they reach him, he loses his grip and falls to the pavement, appearing to strike his head.
Officers and firefighters begin rendering aid.
The man eventually was arrested.
The airline said in a statement to KTNV that the plane was preparing for takeoff en route to Portland as the man approached it on the tarmac.
Police were called, and the airline is cooperating with law enforcement in the investigation.
The jet returned to the gate for a full inspection following the incident.
Authorities told KSNV that mental illness or impairment likely was involved in the incident. The unidentified suspect climbed over a fence to get into the area, they said. It was not immediately clear how serious his injuries were.
The Las Vegas Metropolitan Police Department did not immediately respond to a Fox News request for comment.