The history of jetpacks is long and there have been hundreds of prototypes made all over the world. The most famous is the Bell Rocket Belt. It was powered by tanks of hydrogen peroxide, which decomposes into steam and oxygen, blasting out of nozzles on the pilot's back and thrusting him or her into the air. Before you knew it there were rocket packs popping up everywhere. At the opening ceremony of the Los Angeles Olympics, in the 007 movie Thunderball, even for the audiences at Michael Jackson's Dangerous World Tour. But there was a major problem. The jetpack would only work for 30 seconds at a time, it screamed like a banshee and the pilot had weigh less than 60kg and wear asbestos pants because the exhaust came blasting out at 740 degrees Celsius. Also hydrogen peroxide fuel was very expensive. In the end even the military gave up on jetpack research, putting it into the basket of excess difficulty. It looked like the jetpack would end up a novelty footnote in aviation history. The future would have to wait.
Wikipedia article on the Martin Jetpack.