In a traditional chronograph watch, the button sequence is top (start), top (stop), bottom (reset).
With a flyback chronograph complication, you do not need to sop the chronograph before resetting the stop watch second hand. You start the chronograph (top button) and you can push the second button to “flyback” the second hand or return it to zero, where it starts counting immediately again.
On a traditional chronograph watch, if you try to reset the chronograph without stopping first, you will potentially damage the movement.
This is ideal for situations where resetting the stopwatch function is time sensitive. It takes less time to operate a flyback chrono than the regular stop, start, reset pusher sequence.
Flyback Chronograph History
Although the first flyback style function was invented by Breitling, the flyback chronograph was first officially patented by Longines in 1936.