A bomb is dropped at a point from a moving aeroplane. The pilot observes that:

From the pilot's frame of reference, since the bomb has the same horizontal velocity as the plane when dropped, the bomb continues to move forward at the same speed while falling vertically due to gravity. Thus, the pilot observes it dropping straight down (relative to them). However, relative to the ground, it follows a parabolic path. Wait, the question asks what the pilot observes. The pilot is moving with the plane, so the horizontal velocity relative to the plane is zero. Therefore, the bomb appears to fall vertically downward relative to the airplane.