In the early 1950s, Breitling collaborated with the AOPA (Aircraft Owners and Pilots Association) to make the slide rule of its Chronomat even more relevant to pilots. The end result, the Breitling Navitimer, was a well-conceived tool watch with outstanding legibility. The very first examples came with an all-black dial, but eventually, the sub-registers became white to increase the contrast and make it even more legible. Similarly, the AOPA logo was replaced with the twin-jet logo, and the beaded bezel also evolved. Despite these minute cosmetic changes, the Navitimer remained pretty much identical through the years, proving how well-executed its first draft was.