Don't think the world in 100 years will be very different from today's.
At least not as much as today's world differs from the world in 1908.
No flying flyers most likely will not appear.
Ride will also, on machines with four wheels. Only work they would no longer be on the products of oil refining.
Well public transport will be better, trains on a magnetic pillow, etc.
One thing is for sure, it will be a world without oil, gas, coal and uranium.
All fossil fuels will be exhausted within the 21st century.
And the world would have to change.
The main problem of the world of the future will be energy. On thermonuclear stupid to hope, thermonuclear energy, even if such reactors will be created will cost much more expensive than energy from coal, for example.
What else will and what will not?
Different languages and races are not going anywhere. Will be black and white, yellow and blue =)
Politically the world is unlikely to become one. Different countries will exist. Economically, except that, the planet will rally. But it's already happening.
So the world has changed dramatically, has become completely unified, it is necessary to take place and the dramatic event.
World war, a meeting with extraterrestrial intelligence, the fall of an asteroid =)
I think without skyscrapers, with lots of forests and animals, with clean oceans, seas, lakes,.. . Without borders and States, a free human society.. . A surprising number of creative people who freely with each other communicate and develop! Money is only the form of electronic maps and if they'll ever be needed! I think that people will learn to communicate without the help of improvised means, but using the mind, the subconscious!! ! Not all cars running on oil resources, all kinds of energy resources will move to solar, wind and I think that will open up another source of energy which now little who knows.. . There is no family, just people or groups of people who like to live together, and children will educate all his children will be wiser and smarter.. . Like this I want to see planet Earth in 100 years..