Book 26, Question 93
Why don't we all have jetpacks?
Newer jetpacks can fly longer but are costly, loud, and risky.
In the 1960s, an American team built a rocket belt that could lift one person into the air. But it only flew for about 30 seconds and needed special fuel, a lot of noise, and a trained pilot. Water-jet packs that push a rider up from the surface are fun, but they need to be near water.