The only way you can truly see the effects of inertia in full measure, is in the absence of forces, which is only in outer space. Still you can see its effects, though they are masked by gravitational and frictional forces. When an object is thrown from a flying aircraft, it continues to move with the same velocity as the aircraft, for some time, till it hits the ground, under the effect of gravity. This linear velocity, that it gets from its inertia, makes it fall in a trajectory that is not a straight fall, but a curved one.