My 2 cents, having worked for Nikon for 4 and half yrs...
For what I can see, and from a classic film camera point of view, this picture would be taken by a very large lens, maybe a 600mm or similar, with lots and lots of light (the sun is right above the photographer), resulting in a very closed diaphragm aperture (I would guess an 11 stop) which will focus both fore and background alike, and if the film was sensitive, say ASA 400, you could easily get a shutter speed of 500 or even 1000, that would freeze the image even sitting on a moving airplane, with the hands shaking.
You can obtain a visual effect like this using the right lens and the right light. The distortion of the picture is related to its quality. As you may know, the higher the lens focal distance, the lesser its picture quality, because the light has to cross a lot of glass until it reaches the film, and generally at greater focal distances the edges of the frame will be more magnified than the center.
You could have a good lens putting this view in the correct perspective, generally used in astronomy, the so called reflex lens, because of its mirror inside converging the light to a small number of glass lenses, but it would be 1st-very VERY expensive and 2nd- it would weight a ton and almost impossible to use, specially on board of a plane.
Those guys who know a bit more of photography, will notice this same effect on special cameras, like Hasselblad, that can tilt the lens according to the film plane, and for what purpose? For taking a picture of a building from the middle of the street but making the image look like it was taken from the middle of a building across the street, so the edges of the building look parallel. This is used allot by architects.
I would take a shot exactly like this using the following: Hasselblad Flex Body camera + Carl Zeiss Telephoto lens + Asa 200 film. No kidding.
Just edited to say that the Nikon D100, used by the photographer in question, with a 500mm or 600mm would have make the same effect, not by intentional camera ajusting, but for lens poor quality.
GD&L