This document presents a sensitivity analysis relative to different algorithm design parameters on the attitude performance of two different Global Positioning System/Inertial Navigation System (GPS/INS) sensor fusion algorithms for estimating aircraft attitude angles, namely the Extended Kalman Filter (EKF) and the Unscented Kalman Filter (UKF). The sensor fusion was performed using flight data acquired with three different WVU YF-22 research aircraft under a variety of flight conditions. The attitude estimates were compared with direct 'truth' measurements from an on-board mechanical vertical gyroscope. The sensitivity analysis was conducted on the following parameters: process and measurement noise covariance tuning, IMU and GPS sampling rates, GPS outages, time offset between GPS and IMU measurements, and acceleration due to gravity. Overall, the EKF and UKF performed very similarly in response to the different parameters for this study.