Abstract :
Unmanned planes dominate the battlefield, yet airliners still have - and copilots - Time was when a uniformed man would close a metal gate, throw a switch, and intone, "Second floor-men\´s clothing, linens, power tools..." and the carload of people would glide upward. Now each passenger handles the job with a punch of a button and not a hint of white-knuckled hesitation. The first automatic elevator was installed by Otis Elevator Co. in 1924; the things became common in the 1950s.