The Model 264 was an updated and modernized P-26, differing in having fully cantilever wings of elliptical-design, wing flaps, enclosed "greenhouse" canopy, and retractable undercarriage. The landing gear was similar to the Boeing Monomail, the main wheels retracting backwards about halfway into the wings. The fuselage and the tail were basically the same as those of the P-26. The 264 retained the proven 550 hp Pratt & Whitney R-1340-31 Wasp air-cooled radial, used in the P-26. The armament of one 0.30-cal and one 0.50 cal machine guns mounted in the fuselage sides and firing between the cylinder heads of the radial engine was the same as the P-26A.