UAV-300 is a small, affordable indoor drone built to move through confined spaces and understand its surroundings. The goal of the project is to develop a smart flying system that can move from one indoor location to another, avoid obstacles on its own, create a map of the area, and make navigation decisions using onboard AI. The drone uses a combination of sensors such as ultrasonic and infrared distance sensors, a depth camera, and an IMU to determine where it is and how it should move. A compact AI model processes visual and spatial data so the drone can chart paths through environments like homes, offices, labs, and storage spaces. This project shows that advanced indoor autonomy is possible even with an inexpensive setup, using custom PCBs, 3D printed components, and open-source AI tools. UAV 300 is designed to be expandable and reproducible, making it suitable for future applications including indoor surveying, automated inspections, small-item delivery, and safety monitoring.