This project focused on the design and development of a semi-autonomous firefighting drone built on a custom quadcopter platform integrating a Pixhawk flight controller with a Raspberry Pi for onboard processing, sensor fusion, and mission execution. The system incorporates thermal imaging and LiDAR sensors to detect fire hotspots and provide environmental awareness, along with a mechanism to deploy an extinguishing agent. Development included system architecture design, schematic and pinout creation, and simulation of autonomous behavior in a 3D Gazebo environment, with control algorithms developed in Simulink for deployment onto the flight controller. The drone was successfully assembled and demonstrated stable manual flight, as well as partial autonomous functionality such as waypoint navigation and automated takeoff and landing using PX4 and QGroundControl. While full end-to-end autonomous firefighting was not fully achieved, the project validated key subsystems and highlighted important challenges in real-world deployment, including sensor calibration, state estimation, and hardware reliability, demonstrating the potential of low-cost UAV systems for firefighting and emergency response applications.