This example shows how innovations are difficult to anticipate by simple extrapolations. Who would have thought that lasers would not conquer the world as powerful death rays but as tiny reading devices in every kid's disk-man and CD-ROM drive? That military superiority at the end of the 20th century is not based on space-strike weapons but on a global positioning system (GPS) that not only allows pinpoint strikes but also leads to surprising civilian spin-off? If one looks at cartoons from the fifties about what the world would be like in the nineties one can see the airspace of futuristic cities crowded with personal atomic powered airplanes. Instead today's cars still run on the same old internal combustion engine but one finds one's way through the city jungle with satellite navigation.
It is also fascinating that the dream of individual human flight has not been realized with means of relativistic quantum mechanics or nuclear or even high-energy physics. It was accomplished by finding a smart way to improve an innovation that goes back to the Chinese of more than two thousand years ago, the kite: Modern paragliders only use the wind and materials that were available for thousands of years. Still it was not until the second part of this century that mankind understood enough about the complexity of airflow to make an invention possible that uses the force of the wind itself to give stability to wings strong enough to carry humans all the way up to the clouds.