I've observed a similar effect at MAN. It was one of those afternoons where the weather was changing constantly. A 747 on approach at about 500 feet created the same effect, but it was just too far away for my kit.
Such a shot is possible with a 400-500mm lens. The distance compression effect on a telephoto lense can also create the illusion of a shallower angle between shooter and object, thus creating a false 'air to air' appearance.
I'm fairly confident it's genuine. There's nothing to stop you emailing the photographer, who I'm sure would be happy to tell you how he got the shot.