Uncrewed aircraft systems is a multidisciplinary academic concept and technological domain focused on the design, development, operation, and application of aerial vehicles functioning without an onboard human pilot. This field investigates the complex integration of aerodynamics, control systems, sensor technologies, communication protocols, and operational methodologies across varying scales and levels of autonomy, enabling novel capabilities for remote sensing, data acquisition, operational engagement, and research in diverse environments unsuitable or hazardous for crewed flight.