Longines “Lindbergh Hour Angle”, ref. 989.5215, is a smaller 38 mm version of the classic pilot's watch that Colonel Charles A. Lindbergh had constructed in collaboration with Longines in the early 1930s. The model is directly based on the historical “Hour Angle” concept, developed to facilitate flight navigation over open water before the advent of GPS and satellite navigation.

The rotating inner dial is central to the design. By adjusting it in relation to the minute hand, the wearer can synchronise the time against radio signals and calculate the hour angle, which, along with sextant measurements, provided the pilot's longitude, much like traditional marine, celestial navigation. The result is a wristwatch where function and form are closely intertwined, and which clearly connects to Longines' long history of precision instruments for sports, expeditions, and aviation since the 1830s.