Today, pilot’s watches have specific characteristics that define them. These elements were developed in order to aid pilots in flight, visibility being key. Just like in a car, taking your eyes off the road, or in this case the sky, poses disastrous hazards. During the time when aviation was coming into being, men didn’t wear wristwatches. Pocket watches were the masculine timekeeper of choice, although the wristwatch had been created by Patek Philippe, but for ladies.
The pilot (wrist)watch was born when trailblazing pilot Franco Alberto Santos-Dumont requested his friend Louis Cartier help with the problem of fumbling around with his pocket watch while he was in the air. Up to the challenge, Cartier presented the Santos, a square-shaped watch on a leather band. While the Santos is a far cry from the current aviation standard, it nonetheless holds the distinction of being the first watch designed to assist in flight. But more than that, the Santos also legitimized and popularized the wristwatch as suitable for men. To this day, the Santos remains an icon and is still a staple in Cartier’s lineup.
For a great history of Alberto Santos-Dumont, his aviation pursuits and the first watch that flew, check out the excellent article on Monochrome.