Chilling footage from inside the Frontier Airlines flight captured the moment the plane struck and killed a person on the runway as smoke began pouring into the cabin.

Flight 4345, headed to Los Angeles, struck and killed a pedestrian who reportedly scaled a fence during takeoff at Denver International Airport Friday evening, leaving 'human remains' on the runway.

Newly-surfaced videos revealed what passengers witnessed, including a disturbing clip showing the exact moment of impact, which travelers said 'felt like an explosion.' 

'We're going pretty fast and I felt like the plane started to tilt up when out of nowhere, it just - we felt a thud and heard an explosion,' passenger Jose Cervantas told The National Desk.

'I was right on the wing, so I looked to my right and I see the right wing just on fire,' he added.

One video posted to TikTok showed a passenger’s view from a window seat as the aircraft accelerated along the runway, illuminated by lights against the night sky.

Seconds later, a terrifying bang ripped through the cabin before the passenger’s window flashed bright orange from the impact, triggering startled yelps and rising panic in the background. 

'We immediately came back down, there was fire on the engine, there was lots of sparks that are happening,' one passenger told NBC News.

John Athens, another passenger, told The New York Post: 'When the engine blew up, I thought, "Oh s–t, we’re all going to die."'

'The majority of people didn’t know what was going on or what happened, but there was just a big explosion,' he added. 'And obviously, when you hear a big explosion, people start screaming, kids are crying, and it was horrific.'

Cervantas told The National Desk that the plane landed, 'swiveled side to side' and then shut down completely.

'Then the cabin starts to fill up with smoke and that's when they started evacuating everybody,' he said.

In another video filmed during the chaos inside the cabin, terrified travelers were seen scrambling to escape while exchanging fearful looks. 

Some appeared to be calling loved ones, while others tried to cover their faces from the smoke that began filling the tight space. 

'As soon as we saw the sparks on the flight smoke filled the cabin completely. It was super hard to breathe,' another passenger told NBC.

Passenger Mohamed Hassan told KUSA News that he and others on board were stuck on the plane for about three minutes before evacuation began, during which he said he inhaled 'a lot of toxic fumes.'

Denver International Airport released a statement confirming that a person 'jumped the perimeter fence' near the runway and was hit two minutes later at 11.19pm.

The Frontier Airlines plane, carrying 231 people onboard, including 224 passengers and seven crew members, killed an unidentified individual.

'A trespasser breached airport security at Denver Int'l Airport, deliberately scaled a perimeter fence, and ran out onto a runway,' US Secretary of Transportation Sean Duffy wrote to X, adding that they were then struck at 'high speed.'

'No one should EVER trespass on an airport,' he wrote. Officials who examined the fence said it was intact.

Aviation expert and safety analyst Greg Feith said the breach itself is 'highly unusual,' according to 9News Denver. 

'The biggest question with this particular event is how did this person breach that operational area, getting over a 12-foot fence with razor wire,' Feith told the outlet.

'Were they intoxicated? Did they have some sort of mental issue? Was this an intentional act?' he added. 

'These are rare events when you have someone breaching the operational side of an airport, especially an international airport. 

'Given the security that we all go through as a passenger, that same security really exists in the operational area that is within the perimeter fence.'

An official told ABC News that the victim was at least partially ingested by one of the engines.

One passenger described watching the 'legs of a human' spin around in the engine as the cabin filled with smoke, reported the New York Post. 

At least 12 people sustained minor injuries on the aircraft, and five were taken to local hospitals for treatment. The rest of the passengers were bussed to the terminal and have since left on a new Frontier flight.

In newly released audio, an air traffic control employee can be heard warning pilots of a 'party walking on the runway' just minutes before the fatal accident. 

'Tower, Frontier 4345, we're stopping on the runway. Uh, we just hit somebody… we have an engine fire,' the pilot said, according to air traffic control audio. 

He also recalled seeing the individual 'walking across the runway.' 

'I've got what appears to be a deceased person on the runway,' the employee added. 

The air traffic controller can be heard confirming, 'I do have limbs on the runway,' a recording first reported by TMZ.

Blood was visible in the impacted engine of the Airbus A321, according to photos circulating on social media that the Daily Mail has chosen not to publish.

Other videos shared on social media showed passengers evacuating the cabin via emergency slides, the standard escape route for all on board, including children. 

The Denver Fire Department responded to the scene and extinguished the fire.

The Federal Aviation Administration (FAA), National Transportation Safety Board (NTSB) and Denver Police are all investigating the collision.