The Galileo HAS (High Accuracy System) service can be used in various modes of transport, including air, sea, and road. In the context of air navigation, its potential application in determining the position of aircraft or UAVs (unmanned aerial vehicles) during flight is of particular importance. The main objective of this work is to determine the accuracy of kinematic positioning of UAVs using HAS corrections in the context of air navigation in the field of transport. To achieve this objective, the position of the UAV was determined using GPS/Galileo code observations and HAS corrections, and the accuracy of the determined BLh ellipsoidal coordinates of the UAV position in flight was determined. The aerial research used a DJI Matrice 350 UAV with a Septentrio Mosaic-X5 geodetic receiver installed on the platform with a module for recording HAS corrections in real time in SSR (State Space Representation) format. The calculations were performed using the RTKLIB program, which used GPS and Galileo navigation messages, GPS and Galileo code observations in RINEX format from the Septentrio Mosaic-X5 receiver, and HAS corrections converted to RTCM (Radio Technical Commission for Maritime) format. In turn, Emlid Studio v.1.9 software was used to determine the precise flight reference trajectory using the DD (Double Difference) phase solution. The accuracy analysis shows that the RMS errors for the HAS solution in SPP method are: 0.36 m for the B component, 1.49 m for the L component, and 8.36 m for the h component. The results of the study show the enormous potential of using the HAS service in air navigation. In the future, there are plans to conduct more research using HAS in UAV flights.