That's certainly interesting... not anti-aliasing or wagon wheel though. I don't know about other cameras, but both of mine expose all 'pixels' of the sensor at the same time. An NTSC video camera would be different as it only does half the lines at a time, but a still should just open the shutter, get light, and close.
I've used two different digital cameras with planes, a Nikon D70s (DSLR) and a Canon SD450 (pocket point and shoot), and never got anything like that. Always a true motion blur, like one would expect.
What make and model camera was that taken with?