Original vintage 1957 Breitling ad for its Navitimer, Unitime, and Chronomat chronograph watches highlighting their well-established links to the world's aircraft pilots, both commercial and military.
 
Dimensions: Approx. 10.25 inches wide by 14 inches high
 
"It was the making of complex aircraft dashboard clocks and pilots' watches that inspired Breitling to produce their superb trio: the Navitimer, the Unitime and the Chronomat - the most astounding chronographs of our day."
 
"But now Breitling have taken time off from solving the exacting problems of men of the air, to make a watch for men in other walks of life, who nevertheless share the flying men's appreciation of technical excellence.  Proudly they present their new self-winding calendar watch dedicated to man's conquest of the skies and to men everywhere who demand nothing less than the best!"
 
In the 1940s, Breitling added a circular slide rule to the bezel of its Chronomat models. This bezel became most associated with the Navitimer, launched in 1954 – the name Navitimer comes from two words were used to describe its purpose: Navigation and Timer.  
 
The Navigation part of the name is handled by the ingenious slide rule bezel.  This (relatively) easy to use bezel allows the wearer to multiply, divide, calculate ground speed, miles per minute, fuel consumption, rates of climb and/or descent, distance traveled during climb/descent, and nautical to statue mile conversion.
 
During a time when computers were too large to fit into planes, pilots had a convenient way to make a bunch of useful calculations.  The Timer in Navitimer is provided by its chronograph complication. Like all chronographs of the time, it was a manual wind piece. The first movements were supplied by Venus, with the Valjoux 72 being added to production in 1954.
 
In 1961, Scott Carpenter, one of the original astronauts in the Mercury space program, tasked Breitling with incorporating a 24-hour dial instead of the normal 12-hour dial, due to lack of day and night in space travel.  Breitling produced the 24-hour Navitimer, which Carpenter wore on his 1962 space flight.  Breitling proceeded to produce a commercial version of the 24-hour version, the Cosmonaute Navitimer.
 
The first automatic Navitimer chronograph was introduced to the public in 1969; its movement was co-developed by Breitling, Dubois-Depraz, Heuer, and Hamilton.  Unfortunately for the company, it arrived after Japanese watch company Seiko invented the first automatic chronograph in late 1968.