Looking again at the photo and maps (as well as Google Earth), the road heading away in the left side of the panorama is an east-west street — probably 63rd Street — and we are looking eastward. The fencing that separates the balloon area from the throngs of people outside it is along a north-south axis, and we are looking southward on the right side of the panorama. Just outside the fenced area is the rail line which would be used by the CTA Orange Line if/when it is extended to Ford City.

So it appears to be a 90° east-to-south panorama of Chicago’s West Lawn community area. With balloons.

Looking at this link. It appears that "Chicago Aero Park" was the predecessor to Midway, as that historical place name is marked at the southeast corner of current Midway airport (and the northeast corner of the intersection of Cicero and W. 63rd Sts).

Looking at the Google maps satellite image, it looks like some of the neighborhood around there hasn't changed much since 1908.

Someone is going to know where Aero Park was, right?