The US Army Sky Soldiers Cobra Demonstration Team shows incredible synchronization in this picture. The bottom-most pilot will lose points for the slightly-off rear rotor position.
Important air show photography tip: Helicopters and prop planes in the air with their blades frozen sharp look unnatural to me - like they are going to fall from the sky. Use a shutter speed longer than 1/500 to give the blades some motion blur. The 1/250 shutter speed I was using with this 400mm lens resulted in a lot of motion-blurred shots, but I would rather have a few really good shots than a lot of OK shots.
Camera and Lens Settings
400mm f/16 1/250s
4896 x 3264px