The technology of integer ambiguity resolution enabled precise point positioning (also referred to as PPP-AR) has been proven capable of providing comparable accuracy, efficiency and productivity to long-baseline Real-Time Kinematic positioning (RTK) during the last decade. Commercial PPP-AR services have been provided by different institutions and companies and have been widely used in geodetic missions. However, the usage and research of the PPP-AR mostly concentrated on nonaviation applications, e.g., vehicle navigation, surveying and mapping and monitoring crustal motions. Few of them focused on fixing the ambiguities during an aircraft flight. In this contribution, we implemented the PPP-AR technique for the first time in an airplane flight test to investigate how much the fixed ambiguities could contribute to airplane positioning solutions in the challenging circumstances, including high velocity and severe maneuver. We first looked into the influences of the tropospheric delay on the positioning and ambiguity solutions since the height of the airplane may dramatically change within a narrow time span, and thus a proper constraint of this parameter was crucial for the computation of the tropospheric effects. Then how to fix the ambiguities successfully and reliably in the challenging circumstances was discussed. Finally, the airplane data was processed in 15 s and 1 s interval with ambiguity float and fixed solution under different configurations to illustrate in which condition and to what extent the fixed ambiguities can improve the airplane positioning accuracy.