I would say that the people born before WWI would be the generation that saw the most change.

They saw two world wars, industrial-scale killing in wars, the advent of the airplane and air travel, as well as the invention of antibiotic medications, widespread vaccination programs that eliminated diseases that used to kill large numbers of people (eg, smallpox, polio, etc). Electric power went from a laboratory curiosity to something in most all homes, many of this generation lived long enough to see man walk on the moon.

From the horse-n-buggy era to the moon in one lifetime - I don't think there is any generation that has been able to compare in terms of change.