Think Los Angeles at rush hour is bad? Try doing it half-blindfolded with nothing but a radio and a few blinking lights to show you the way. That's how pilots navigate the invisible highways in the sky, and there's a beautiful design that makes it all work. It only took about a hundred years to come up with it.
When you take a step back and think about it, airspace design—and the air traffic control system that dictates it—is a small miracle. Actually, it's a pretty big one. This complex set of rules, developed and refined since the early days of aviation, keeps planes from crashing into each other or slamming into the ground when trying to land in bad weather. Incidentally, it was these very kinds of tragedies that prompted authorities to write the rules to begin with before technology took the reins, shaping the way we fly today. In the next ten years, technology will transform it all again, but I'll come back to that. First, let's get our history straight.
It all started back in the 1920s when the most prominent pilots in the United States were actually mailmen. These guys would fly by-planes from coast-to-coast along the original transcontinental airway. (Even Charles Lindbergh got in on that action.) In 1927, having realized the business potential of passenger air travel, the Department of Commerce took control of the airway from the U.S. Postal Service, and the nation's first air traffic control tower opened three years later in Cleveland. Before that, pilots relied on hand signals or flags—even giant arrows—on the ground for signals. Aside from that single superhighway connecting the coasts, though, all of America's airspace remained uncontrolled.