It's been four years since I first spoke to David Mayman over the phone, in the afterglow of his pioneering jetpack flight around the Statue of Liberty. Since that day, things have moved along at a rapid pace. Jetpack Aviation has developed a number of new jetpack models, multiple pilots are now training under Mayman as the world's only fully FAA certified jetpack instructor, and a growing number of people have now seen an honest-to-god jetpack performance in person.

Until this past weekend, I'd only seen the thing fly in videos. But on Sunday, to celebrate the world premiere of a documentary about his work, Mayman put on a demonstration flight in Sydney Harbour, and I flew up from Melbourne to see Mayman fly in person for the first time.

I reckon the whole of Sydney would've heard that flight. Most of them probably just thought there was an F-18 in the area, but there wasn't – that fearsome roar was coming from the two small contra-rotating jet turbines mounted to gimbaled arms on David's backpack full of kerosene. The sound waves from the JB-10 go right through you, shaking every spine in the area. It's shock and awe and cortisol and adrenaline.

And then, there's a man hanging in the air, rocketing past at fearsome speeds, the Sydney Opera House glinting in the morning sun behind him. You see planes and choppers in the air every day, but this is the difference between watching car and motorcycle racing – now, there's a human form at the crux of it all. Unshielded from the wind whipping into his face, and unshielded from horrifying injury if there's a mistake or a malfunction.

It seemed like every age-battered journo in Australia was there yesterday morning. These people have seen it all, the job can make you jaded and cynical and snide. And every single one of them was gasping in sheer, unadulterated, childlike amazement at what was happening in front of them.

Mayman, for his part, is having fun. Thundering past at high speeds, turning lazy pirouettes, taking his hands off the yaw control throttle to give a cocky thumbs-up to the news helicopter, lowering himself down close to the water so the ferocious air jets he's riding on can whip the water into curling vortices below him. I catch the hint of a smile as he zips past on another fly-by, and lose my shot through the camera because I'm involuntarily waving at him like a kid at a fire truck.

Five long minutes he's out there in the air, making people shake their heads and blink like they're watching a magic trick. And then, as he's done on hundreds upon hundreds of free flights now, he brings himself to a controlled landing on the pontoon beside the Opera House, and the JPA team hangs buckets of water off the ends of the turbines so cool them off. He stands there, grinning, throwing up so much steam that he looks like he's on fire.

Off to the side, as the cameras close in on David, a slight woman with short hair and two cameras hanging off her shoulders is wiping tears of relief and pride from her eyes. It's Mayman's sister.

She tells me this is the second time Mayman's tried to fly Sydney Harbour. The first time was 10 years ago, using a hydrogen peroxide rocket belt built for him in a back yard by a Mexican rocket maniac. A belt that had failed on his second-to-final test, smashing Mayman into the ground and pouring so much rocket-grade peroxide down Mayman's leg that it ate through the skin right down his leg, and through into the muscle.

He hadn't waited for the skin graft, he'd just wrapped the leg in bandages and gone straight back to hammer the rocket belt back into shape for one more test. And then he'd limped out two days later onto Sydney Harbour and taken off, full of faith and bloody-mindedness, and misjudged his tiny fuel load, and crashed into the water, weighed down by the rocket belt.

The divers got him up out of the water, and by some divine provenance or work of medicine he managed to avoid serious infection in the soaking-wet open wound running from his right bum cheek down to his calf, and he got to keep his leg. But it's fair to say the last attempt nearly killed him, and it's no small relief for David's sister when her fearless brother nails a perfect landing this time.

So yes, I've been reporting on Mayman's aerial heroics for four years now, but I only picked up the story after his stunning first demonstration flight around the Statue of Liberty in 2015. And I've always thought of Mayman as the sensible one out of the upcoming crop of jet-powered personal flight pioneers.

He's a qualified commercial helicopter pilot, he does proper flight plans and pre-flight checks. He informs aviation authorities, fills in the required paperwork and generally approaches this wild flying man business with about as much caution and responsibility as is prudent and possible when you're dealing with pioneering personal flight devices. But I've missed about a decade's worth of the journey, and it's been a very sketchy and treacherous decade indeed. And I'm about to have those years filled in, in a feature-length crash course.

Own the Sky: the Documentary

Gregory Read is a high-school mate of Mayman's. Long before Mayman was leaving the ground behind, the two of them were young Sydney ratbags, making fireworks and rockets in the back yard.

As Mayman moved off into the business consulting world, Read went into the movie business. And each of them made a go of it, Mayman eventually selling his business and putting himself in a position where he could go and pursue his weird and vastly expensive jetpack dream, and Read becoming a successful producer and director in drama and documentaries.

When Mayman told Read he wanted to build a jetpack, Read said "well that's nuts, I've gotta film that," and so began a truly remarkable decade-long collaboration between the two friends. In between working on other projects, Read made sure to catch up with Mayman whenever possible, bringing a camera along to every major step on Mayman's crazy journey. And the resulting documentary, Own the Sky, had its world premiere in Sydney Sunday night.

I'm no kind of movie reviewer, but I love innovators and wild men, and to me, Own the Sky does a better job than anything I've ever seen of chronicling the painful, prolonged birth of a groundbreaking innovation.

Mayman's story is the story of human flight itself. We look back at the Wright Brothers as fabled groundbreakers a century later, but to their families and loved ones, they must've looked like absolute maniacs, trying to launch themselves skyward on nothing but the power of their own ingenuity. Putting their own lives at risk in service of an idea.

You need to be a special kind of crazy to do this stuff. You need to take giant leaps of faith. You need to bounce back after injuries and knock-backs and the hundredth failed prototype flight. You need to be so driven that everything else takes second place, even if it's your body or your family. Read's film is unflinching on this point, with some heart-rending interviews with Mayman's wife and daughters underscoring just how much this venture has cost them all – and how much more it's nearly cost on so many occasions.

It's flat-out terrifying watching Mayman grapple with his earliest prototypes, being flung from wall to wall in the Van Nuys backlot where he began building and testing them with famed engineering genius Nelson Tyler. Watching David's team wrestle him out of that Mexican rocket belt as it begins to spit flames and glow red-hot, knowing that if that fire reaches the peroxide tanks, it'll go off like a stack of dynamite. Watching him gasp for breath as the dive team pulls him out of Sydney Harbour after that first failed flight. I reckon my heart was pounding out of my chest for a solid 60 percent of the whole film.

It's also hilarious – how could it be anything else watching these cowboy engineers struggling to fight gravity? Mayman's eternal determination and relentless drive seem like a source of constant amusement to Nelson as he struggles to keep things somewhat within the boundaries of safety and sanity.

Some of the film's most touching scenes also deal with a kind of passing of the torch. Nelson Tyler worked on rocket belts back in the 70s and 80s, building the device in which Bill Suitor made his spectacular flight at the 1984 LA Olympics.

Both Tyler and Suitor have dreamed ever since their early work of a proper jetpack capable of more than 20 seconds of flight, and as Mayman teamed up with Tyler to begin building JB-series prototypes, the pair invited Suitor to come in and advise. It's a rocky path, but Suitor's tearful pride as he watches Mayman's final triumphant flight in New York is a wonderfully emotional moment.

Own the Sky is a remarkable film. Its subject is an absolutely unique and fascinating figure, and nobody but Greg Read, with his boundless energy and unfettered access, could've made it. It's a remarkable double leap of faith – Mayman never knowing whether he'd ever finally achieve his dream of human flight, and Read never knowing if he was following Mayman all over the world for nothing, whether there'd ever be a movie in the tens of thousands of hours of footage he compiled over a decade of work.

It's beautiful, and hilarious, and terrifying, and honest and real. It's a stunning testament to innovation, and risk taking, and invention and unstoppable will. It nakedly shows the two most valuable things that pioneers bring to the table – endless failures outweighed by even more endless resilience. I can see this being an incredibly inspiring film for other inventors, particularly if they're in the trenches right now struggling with failure and despair like Mayman does for much of the film. His overnight success took more than a decade.

This film had me in tears several times, and cheering like a fool at others. I was proud as hell to be there for the premiere. Most of all, it underscored for me my admiration of Mayman and other innovators like him, who put their money, their passion and their own asses on the line to push things forward. Folk like David are a big part of the reason why I do this job, and whatever small part I can play in telling their story is a privilege.

And if I ever thought Mayman was "the responsible, sensible rocket man," well ... that's only because I never knew him when he was younger, and a complete psychopath. His maturity has been hard-earned through a thousand mistakes, and having now seen the path that brought him to Sunday's redemption flight at Sydney Harbour, I can totally empathize with his sister in her pride and relief.

Own the Sky will be released internationally on November 18th. I thoroughly recommend you check it out. Like the doco on Facebook to be updated with where and when you can catch it – it'll be on Amazon, Hulu and Apple TV in the United states, and there'll be a theatrical release in Australia.

Enjoy our video of the Sydney Harbour flight below.

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