LOS ANGELES — Two extreme athletes in wingsuits who leaped to their deaths from a cliff in Yosemite National Park were trying to fly through a notch in a ridgeline and were airborne for about 15 seconds when they slammed into a rocky outcropping, a friend said Monday.

Dean Potter, 43, and his climbing partner Graham Hunt, 29, were both experienced at flying in wingsuits – the most extreme form of BASE jumping, which is itself a sport so dangerous that enthusiasts keep lists of the dead.

Professional climber Alex Honnold, who knew both men, confirmed Monday that their bodies were found in the notch they were trying to fly through Saturday after jumping off Taft Point, a promontory about 3,500 feet above the valley floor.

Honnold called Potter an inspiration and a leader in the climbing community.

“It’s more of a calling or a vocation. He considered himself an artist. It was almost like a spiritual pursuit. He definitely wouldn’t call it a job,” Honnold said.

Hunt lacked the sponsors Potter had, and made money cleaning the park, but “was a good climber, a great base jumper and he was maybe the most prolific base jumper in the valley right now,” Honnold said.

With webs between their outspread arms and legs catching rising air currents, wingsuit fliers have learned how to glide silently downward just beyond the face of cliffs.

As if that doesn’t pump enough adrenaline, they also try to zoom through rocky outcroppings and just over treetops.

BASE jumping – a renegade sport which includes jumping off buildings, antenna, spans (such as bridges) and Earth (in this case, the cliffs over Yosemite Valley) – is illegal in national parks. Most people who try it use parachutes. Doing it in a wingsuit is even more dangerous.

Potter knew the risks, and relished the feeling of cheating death.

“I love the idea that I can change the worst possible thing to the best possible thing: dying to flying,” Potter says in “Fly or Die,” a documentary about his wingsuit jumps that can be seen on National Geographic’s website.

“The wingsuit is basically the flying squirrel suit,” Potter says in the video.

“Everyone kinda fantasizes about it – flying. And it’s an amazing place in history right now, that man actually has the skills to pull it off.”

This time, their skills weren’t enough. When they didn’t soar into the valley, friends alerted park rangers to begin searching – the same authorities both men had sought to avoid when they prepared for the illegal jump.

Park ranger Scott Gediman said a helicopter crew spotted their bodies Sunday morning. Both wore skintight wingsuits with batwing sleeves and a flap between their legs. Neither deployed parachutes, Gediman said.

Friends remembered how Potter spoke about the death-defying nature of the sport at a memorial service last year to a friend who died in a BASE-jumping accident.

“He always recognized how dangerous the sport was and at the same time, how magical it was – the tension between those two things,” fellow climber Chris McNamara said.