Planes in formation, Douglas O-46

 Three Douglas O-46s in the hands of the National Guard fly past the Empire State Building. New York I recognize but I had to look up the O-46. The Douglas company built a succession of observation planes starting with the O-31- released in 1930. Improvements were made over a few models which culminated in the O-46, of which 90 were built. The O-46 was obsolete by World War 2 and it was the last observation plane built by the company.

Boeing