Your author was trained as a military air traffic controller back in the early 1950's, earning both military (USAF) and civil (CAA) ratings. Over the intervening years it has been wonderful to see the changes and improvements in tower design and equipment.

Many today who bother to notice the enormous glass-windowed towers at modern airports cannot appreciate just how much control towers have changed. So too have the skills and abilities of the men and women who perform their important duties from high above the flightline.

Early control towers were simple wooden structures built near the flightline or ramp where airplanes were parked. On military bases they were close to the flight operations building, known as Base Operations. Many of those early towers were open platforms, merely a deck atop a building or a structure of poles and framing. Windows and enclosed weatherproof observation areas came along later. Air traffic controllers were originally pilots, because they knew and understood the needs of those doing the flying.

Before radios came along the few primitive towers that existed, generally at military airfields or busy civilian airports, were equipped with hand-held signal lights, binoculars and a flare pistol. Signals to pilots were simple. Different colored flares or lights indicated go or no-go for take-offs or landings. At military airfields flares also indicated actions to be taken by squadrons of planes, such as start engines, taxi to the take-off position, and take-off. Landings too were controlled by a variety of light and flare signals.

A wind sock would blow to indicate the wind direction and hint at the velocity so pilots could determine the best way to go. Landings and take-offs into the wind were preferred, but other factors could also determine which way to go. A rotating light beacon, atop the tower or nearby, was used to indicate the type of airfield and weather conditions. Military and civil airfields used different light beacon patterns. It was the tower operators who monitored the airfield activity and signaled pilots and ground crews.

Eventually towers got telephones and radios, enabling operators to signal more efficiently. By radio they could tell pilots what runways were active, where to taxi, which way the wind blew, altimeter settings and when to move or stop. Light signals became backups in case of radio failure. By telephone tower crews could advise fire and rescue people when their critical services were needed. As traffic increased the job of tower operators became ever more important. Training and certification became necessary and the job evolved into a highly specialized profession.

Along came more advanced equipment. Radar was added to towers in the late 1940's and early 50's. Now tower operators could see air and ground traffic in darkness or bad weather. That markedly improved safety and performance. But it also added more tasks for the harried operators. In addition to controlling airplanes in the vicinity of the airfield, they also had to manage ground traffic including airplanes and a variety of vehicles. Specialties developed with some people concerning themselves with planes taking off or landing, as well as flying around in the traffic pattern.

As airplanes and electronic systems improved it became possible to guide pilots to airfield approaches and landings by radar and other instruments. New air traffic control specialties were needed. Ground Control Approach (GCA) specialists were trained to aid pilots landing in bad weather. The traffic around airports was soon apportioned to different experts, to those who monitored and controlled airplanes beyond the immediate airport area and then to those within the five mile radius circle managed by tower operators.

During the Cold War years, with high performance fighters standing ready to scramble and intercept in-coming enemy bombers, new complications in air traffic control were added. Special climb-out corridors were designated, priority airspace where those interceptors could go without interfering with other traffic, military or civilian. The air space in and around airfields was becoming more complex, divided and managed. Tower operators had more things to worry about.

In modern times the needs of busy control tower operators demanded new equipment. Improved radios, radars and even computers were added to facilitate the work. Coordination between air route traffic controllers, approach controllers and tower operators became increasingly more important. The tools and technology to do the job safely and efficiently eventually came along.