*Update Feb. 18, 2012: @flyingwithfish has done a very intriguing analysis that proves this image is a work of art vs a multiple exposures, our apologies. From the actual planes/airlines seen in the picture, to the takeoff positioning relative to the airport;@flyingwithfish’s post is a worthwhile read.
– The size of the planes are all relatively the same in the image but not in real life (e.g., Boeing 747s and 777s)
– Several of the airplanes/airlines do not serve Hannover (e.g., Air NZ Link ATR-72-500)
– An actual multiple exposures shot so many times for each aircraft shown in this image would result in an overblown white field (and things in the background like cloud formation would likely have changed)