Certainly a trainer - dual controls with the rear seat facing forward. Not a scout, as scouts typically had 1 seat and a gun (the early fighters, you see, were scout planes modified to carry a gun or two). In a twin-seat scout, the back seat would face aft, with a gun. Looked like a 4-cylinder liquid-cooled inline engine, which would be appropriate for a WW1-vintage design, possibly just post WW1 but before WW2. Both top and bottom wings were the same length and width, for light wing loading which makes for good lift and maneuverability (depending on the control surface areas). Maybe a Curtis JN "Jenny", once used for carrying air mail? Maybe I'll poke around and see if I can identify it properly.

Enjoy!