Step 1: Understand the concept of inertia of motion. According to Newton's First Law of Motion, an object in motion will continue in its state of motion unless acted upon by an external force. This means that when the body is released from the balloon, it will initially continue to move in the direction it was moving (upward with the balloon).

Step 2: Analyze the forces acting on the body after release. Once the body is released, the only force acting on it is gravity, which acts downward. The upward motion due to inertia will not continue indefinitely, as gravity will eventually decelerate the body.

Step 3: Conclude that the body will indeed move upward for a short time after being released, due to inertia. However, it won't keep moving up indefinitely as gravity starts decelerating it. Ultimately, it will reach a point where it will stop rising and then begin to fall.

Therefore, the statement is true only in the initial phase after the body is released.