A flier on the Air Canada jet involved in LaGuardia Airport’s deadly crash told The Post on Tuesday he witnessed passengers’ humanity rise to the occasion even at their darkest hour.

Survivor Jack Cabot, 22, recalled seeing “blood everywhere” after the crash, including on the passenger next to him, who injured their face and had blood gushing from their nose.

“Some people really stepped up in that moment, they organized themselves as a group,” he said of the hordes who rushed to help those around them.

“People were sharing coats. One person used a COVID mask to wipe blood off another person’s face.”

Cabot — who was in seat 18A in the middle of a plane near the wing on the left side — said it took about two hours for everyone to get off the plane and that passengers toward the front of the aircraft had gotten badly stuck and required a lot of help to get free.

The plane’s two pilots were killed in the horror, and dozens of people were injured.

Among those hurt was a flight attendant who was hurled 300 feet from the plane on impact — and found on the ground still strapped in her jump seat.

Earlier in the flight, before the crash, that same flight attendant gave Cabot a beer, he said.

“It led to my new motto: ‘Sit in the middle of the plane and have a beer,’ ” he told The Post.

Cabot also recalled how, after the deadly crash, a young girl traveling alone for the first time was quickly joined by an older British woman, who sat with her throughout the ordeal.

“There’s always some humanity. Always people trying their best,” he said.

“I’m feeling particularly rattled. It’s not every day you get into a plane crash,” the flier said.

The Bombardier CRJ-900 jet originating from Montreal with 72 passengers and four crew on board was in the process of landing just before midnight when it collided with a Port Authority fire engine responding to an unrelated emergency call.

Cabot said nothing felt out of the ordinary until the “crazy 12 seconds” when the crash took place.

“It felt like the landing was immediately off,” Cabot said.

“There was an incredibly loud bang. It was a really, really hard landing.”

“I still feel like I was one of the lucky ones. There were other people in a lot of pain,” said Cabot, adding that he suffered whiplash from the crash and was waiting to hear if he had a concussion.

Asked when he would be flying again after what he’d just been through, Cabot responded with typical New York City resilience: “As soon as I can.

“I don’t want to let this get in the way of my life.