Breitling's iconic Navitimer might just be the most recognisable pilots watch on the market. Its name, a portmanteau of 'navigation' and 'timer', points squarely to its intended use as a pilot's tool. First released to the public in 1954, it was produced with a plethora of dial variations. While many had the 'Navitimer' text, some were signed with 'Geneve' or 'Cosmonaute' writing. The most recognisable feature, however, is the slide rule bezel that allowed pilots to make on-the-go calculations using their watches. While it's since been superseded by electronic computers, its presence on Breitling's watches still provide a reminder of just how challenging of a field aviation was.