This thesis presents the system-level configuration and validation of PX4-based Unmanned Aerial Vehicles integrated with a VICON motion capture system within the indoor flight arena facility of Politecnico di Torino. The work focuses on enabling reliable indoor localization and autonomous flight through the correct integration of external motion-capture data into the onboard estimation and control architecture on the PX4 autopilot. The developed setup involves multiple UAV platforms equipped with PX4 autopilot and companion computers running ROS~2. Motion-capture pose measurements provided by the VICON system are distributed over the local network and processed on the companion computer before being delivered to the flight controller as external odometry.