The Curtiss P-1 Hawk was the first US Army aircraft to be assigned the P (Pursuit) designation. The first production P-1, serial number 25-410, was delivered on 17 August, 1925. P-1 and a similar variant, the P-6 Hawk, were flown by the 27th Pursuit Squadron at what was then known as Selfridge Field, in the late 1920s and early 1930s. The location of the aircraft in this photo is unknown.