This occurs during the scene where Erik (Magneto) lift's Shaw's submarine from the water. When Erik first begins trying, his is standing on the front landing gear of the Blackbird. Specifically, he is on the left wheel of the front gear. He holds onto the gear with his right hand and extends his left arm in order to lift the sub. As the sub comes out of the water, it is to the Blackbird's left. Hank (the pilot) looks out the left window to see the subs's massive rotors in the air.

But when Hank increases throttle and moves the Blackbird directly forward, suddenly the sub is on their right! Erik is now seen standing on the right wheel of the front gear, holding on with his left hand & extending his right arm. The exact opposite of what he was doing just a moment ago!