Glenn Martin, from New Zealand, described his craft as "the world's first practical jet pack" while unveiling it in front of a crowd of thousands at a Wisconsin air show.
The Daily Telegraph reports how Martin's 16-year-old son, Harrison (pictured) donned a helmet and eased into the contraption - with the help of two people to stop him toppling over.
Revving its engine, Harrison slowly climbed to about three feet off the ground and hovered for 45 seconds before touching back down to Earth.
The crowd at the AirVenture Oshkosh 2008 show cheered.
"Wow, that went better than expected," dad Glenn said afterwards. "People will look back on this as a moment in history."
The Martin Jet Pack is theoretically capable of flying an average-sized pilot 30 miles in 30 minutes on a full tank of fuel - it carries five gallons.
The inventor, 48, who has been working on the pack for almost three decades, plans to start selling them next year for around £50,000.
The device is designed to conform to the Federal Aviation Administration's definition of an ultra light vehicle - one weighing less than 115 kilograms and capable of carrying only one passenger - so it won't require a pilot's licence.
Most previous jet packs have lasted only a few minutes before running out of fuel. But Mr Martin, who gave up his job to concentrate on his design, hopes its superior performance will win over sceptics. (Daily Telegraph)