Unmanned systems are one of the fastest-growing and widely developing technologies in the world, offering many possibilities for a variety of research fields. This book comprises the proceedings of the 2021 International Symposium on Unmanned Systems and the Defense Industry (ISUDEF), a multi-disciplinary conference on a broad range of current research and issues in areas such as autonomous technology, unmanned aircraft technologies, avionics, radar systems, air defense, aerospace robotics and mechatronics, and aircraft technology design. ISUDEF allows researchers, scientists, engineers, practitioners, policymakers, and students to exchange information, present new technologies and developments, and discuss future direction, strategies, and priorities in the field of autonomous vehicles and unmanned aircraft technologies.