I'm assuming this is stemming from a discussion about the 4 forces. We all remember that the sum of all forward forces equals the sum of all rearward forces. Due to gravity, weight plays a role in this equation when not in level flight. For example, in a descent, weight does not act parallel to the vertical axis, but rather slightly in front of it. This means that technically, part of the weight of the airplane is adding to the thrust component. The exact opposite is true in a climb, where weight adds to the drag component.