Frontier flight aborts takeoff after person on Denver runway struck

A person who scaled a perimeter fence at Denver International Airport reached the runway and was struck by a departing Frontier Airlines jet within two minutes, a sequence that turns the incident into a stark security failure at one of the country’s busiest airports.

Frontier Airlines Flight 4345, an Airbus A321 bound for Los Angeles International Airport, was carrying 224 passengers and seven crew members when the collision happened on Runway 17L during takeoff. Airport officials said the incident was reported at about 11:19 p.m. local time Friday, May 8, 2026, and the person is not believed to have been an airport employee.

The abrupt impact triggered smoke in the cabin, and the pilots aborted takeoff. A brief engine fire broke out and was quickly extinguished by the Denver Fire Department. Passengers evacuated down emergency slides, and one pilot could be heard telling the crew, “We just hit somebody. We have an engine fire.”

Denver officials said the pedestrian jumped the perimeter fence about two minutes before being struck while crossing the runway. Transportation Secretary Sean Duffy said the person deliberately scaled the fence and ran onto the runway, putting the focus squarely on how a person reached an active airfield boundary and crossed into the path of an airliner.

The airport said the fenceline is intact, but security was inspecting the east perimeter fence Saturday morning for any gaps. The National Transportation Safety Board has been notified, the runway was temporarily closed during the investigation, and local law enforcement is investigating the breach with support from federal aviation authorities, including the Federal Aviation Administration and the Transportation Security Administration.

Officials said 12 passengers reported minor injuries and five were taken to local hospitals. By Saturday morning, most of the passengers had left Denver on another Frontier flight, but the episode left a larger question hanging over the airport’s layers of protection: how a runway breach unfolded so quickly, and whether surveillance, perimeter controls and response protocols were enough for a major hub handling hundreds of passengers on a late-night departure.