I read an article somewhere around 1960 that predicted we'd achieve travel at the speed of light in 25 years (I forget the real number, but within the lifetime of many people living then), and exceed the speed of light shortly thereafter. He based his prediction on the increases in speed of travel over decreasing spans of time, starting with people running, then tens of millennia later horseback, then a couple millennia later steam ships and trains, then a century later airplanes, then sixty years later orbital space travel.