CHRISTCHURCH, New Zealand — Glenn Martin was sitting in a bar with his college buddies 35 years ago when they got to wondering: What ever happened to flying cars and jet packs?

The next day, the New Zealander began looking for answers in the science library, triggering a lifelong quest to build a jet pack.

But today, with the company he created seemingly on the verge of triumph, Martin worries his dream is slipping away.

Martin Aircraft Co. says it will deliver its first experimental jet packs to customers this year, a big development for the new technology. But the jet pack is being designed for first responders like firefighters, an outcome that falls short of Martin's vision of a recreational jet pack that anybody could fly.

The inventor has now left the company he founded. What's more, he says, he's asked for his name to be removed, though the firm's chief said a formal request hasn't been made.

“All us guys know what a jet pack's for,” he said with a smile at his Christchurch home. “With a jet pack, you save the world and you get the girl. Right?”

Jet packs have often been portrayed that way in books and movies. They have formed part of humanity's utopian future vision for the past century. Fictional characters from Buck Rogers to Elroy Jetson have used them, and a real jet pack wowed the crowd at the opening of the 1984 Olympic Games in Los Angeles.

Martin, 56, grew up in the South Pacific, thousands of miles from Houston. But he followed the space race avidly.

“I still remember sitting in class and listening to Neil Armstrong step onto the moon,” he said. “And I believed, I suppose, that we would all have flying cars and jet packs and bases on Mars by the time I was an adult.”

Storied though they may be, jet packs have a troubled history. The Bell Aerospace rocket belt, developed in the 1960s, showed the technology was possible. However, that jet pack couldn't carry much weight and could remain airborne for less than 30 seconds. It was for show, nothing more.

In the mid-1990s, three Houston men decided they'd try to make one. Instead, they made a mess. They fell out over money, and their venture ended with an unsolved murder, an abduction, a man in jail and a device that had vanished.

Peter Coker, Martin Aircraft's chief executive, said he believes the best business plan is to make jet packs for first responders and later for other commercial operators. Once all the supply chains are in place, he said, the company can then turn its attention to building a personal jet pack.

“We are now an aviation company,” Coker, 60, said. “Before, it was very much the kiwi dream. But you have to take that commercial path.”

Glenn Martin's vision still holds true, Coker said: Creating and selling a personal jet pack remains part of what the company is all about.

But Martin doubts the company will ever make one.

When he began his research, he wanted to improve on the Bell rocket belt and make a jet pack that could lift a solidly built guy like himself and a safety parachute, then stay airborne for at least 30 minutes. He decided to use ducted fans, making the word jet pack something of a misnomer.

During the 1980s, he worked in the pharmaceutical industry and built prototypes in his garage. He sponsored two university students to check his math. By 1997, he needed a lightweight pilot, so he enlisted his wife, Vanessa, to make the inaugural flight. It lasted a few seconds.

More refinements eventually allowed the jet pack and its pilot to remain airborne for several minutes and complete controlled turns. Martin took inspiration from reading the Wright brothers' journals; in 2008, he took a prototype to the Experimental Aircraft Association air show in Wisconsin.

He said he decided to build his jet pack with straightforward components, including a piston engine that uses standard gasoline. He wanted to keep it small enough to be classified as an ultralight aircraft, which in the U.S. doesn't typically require a pilot's license to fly. He figured anyone could learn to fly one after a three-day course and be kept safe with a built-in parachute that would automatically deploy in an emergency.

But as he sought to raise funds for his fledgling company, Martin said, he began losing control. Along came investors, venture capitalists and plans for an initial public offering.

The company was listed on the Australian stock market in February last year and is now majority owned by a Chinese company, KuangChi Science. It's valued at about $138 million, showing that investors are taking the concept of a commercial jet pack seriously.

Disillusioned with the direction the company was taking, Martin resigned as a director in June. He still owns a 10 percent stake, which he cannot sell before February.

“I'd picked up the rugby ball and taken it almost to the finish line and felt it was time for other people to do the rest,” he said.

Martin said he's disappointed he didn't see the concept all the way through. On the other hand, he enjoyed a summer holiday with his family this year for the first time he can remember.

“Jet packs are a funny thing. They create a lot of passion,” he said. “Everybody loves the idea of a jet pack. But the reality is that it's a lot of hard work.”