Currently, when modeling either aircraft noise or emissions with the Aviation Environment Design Tool (AEDT), there are simplifications associated with the methodology suggested for determining the aircraft gross takeoff weight [Ref. 1] that can create inaccurate results, along with the inability to model reduced thrust/power departures. The goal of this project is to develop a functional relationship between stage/trip length and weight that can improve the existing guidance provided for weight estimation; and subsequently to determine the percentage of departures that use reduced thrust and the level of reduced thrust that is used for the departure.