Nothing can make a thread unintelligible like a giant picture.
Can I suggest a thumbnail promomag?
I also , was going to say that it does look like a bird at first glance. Even though its an old picture the airplane is traveling at least fast enough
to fly , so the film speed seems to have been quick on this picture.
The most obvious object looks like a "spotter" balloon. They've been used since the Civil War, and are still used today, albeit with cameras rather
than a person in a gondola.