RE: power of observation
My first question is whether the photo is authentic.
I question this for two reasons:
First, when I download it, then magnify it, there are visible distorations around the P-39 and A-26 shich do not appear around the P-51A
Second, the shadowing on the P-39 does not seem to match that of the P-51A (Note the side in shadow comparatively). This could be due the P-39 slight tilt to port, however.
The photo appears to have been taken in late spring as there appears to be snow on the elevated ground in the photo's forground.