Following up on what Cyclonic said, I made a small folder to point out some details. The line which I drew directly north from the planes matches the direction of the shadows cast by the trees directly below the planes. So the picture was shot at just about local standard noon time. If you follow the line north you should theoretically find the shadows.But if you look carefully at tree shadows, you will see a shift in shadow direction where I placed the placemark titled "Shift is right about here" There may well be others further along up the line. Their shadow will most likely be in a frame of film shot at another time.

Notice how large the planes appear compared to the houses and other ground features. This is not only a clue that the planes are high up, but also that they were captured by aerial photography. The plane that took their picture was considerably higher than they are, but not nearly so high as a satellite in orbit. Planes that are at relatively high altitude leave no discernable shadow. A plane near ground level completely blocks the sun. One a bit higher eclipses only part of the sun. And one higher still eclipses such a small part of the sun's disc that it doesn't cast a shadow as it passes overhead.

So even if the planes and their projected shadow were in the same frame, they would probably not cast a visible shadow.

Add to this the likelihood that any shadow would likely fall on a wooded area, and you can see why its not all that surprising that there is no shadow.