Jetpacks: why aren't we all flying to work?

It's not as if the tech hasn't shown promise, but jet propulsion has never become part of our daily lives. Here's why

Those of a certain age may remember the opening ceremony of the 1984 Olympic Games in Los Angeles. As Rafer Johnson lit the eternal flame, a man strapped into a rocket-propelled backpack launched himself across the arena above the ticker tape and balloons, landing gracefully on the track before a TV audience of 2.5 billion.

It was a moment of triumph seeming to herald a new age in which, finally, teased for decades by Buck Rogers' "degravity belt" and King of the Rocketmen, we'd all soon be fizzing off to work with our own personal jetpacks. Even Isaac Asimov confidently predicted that by the turn of the century, they would be "as common as a bicycle".