The Pathfinder was an attempt by the Keystone Aircraft Corporation to develop a civil transport version of the successful series of bombers that it was producing for the United States Army Air Corps as the LB-5 and its derivatives.

The first Pathfinder (registered NX179) was chosen by US Navy pilots Noel Davis and Stanton Wooster for their attempt at the Orteig prize to cross the Atlantic.

On 26 April 1927, a week before their planned departure, the aircraft crashed during a heavily laden test flight from Langley Field at Hampton, Virginia.

Unable to climb quickly enough to clear a row of trees, Davis attempted to turn the aircraft, but lost height and was forced to land.

The second Pathfinder (NC5317) was fitted with extensions to its lower wing that was used to carry a neon sign advertising Silver Dust laundry soap through the skies of New York City at night during 1928.