The objective of this proposal is to develop a cloud-based platform for generating and simulating autonomous flight scenarios, with a specific focus on trajectory planning and risk assessment within UTM/ATM contexts, while also ensuring compatibility with XR HMI systems. The development of PRISMA project will provide a technologically advanced platform that empowers operators to design highly realistic autonomous flight scenarios, providing cutting-edge tools to craft customized scenarios, encompassing detailed elements such as airports, vertiports, moving and fixed obstacles, traditional air traffic, drones, weather conditions, and more. The platform's core emphasis will lie in trajectory planning, optimized flight path generation, and risk evaluation. Its development represents a crucial stride towards advancing autonomous aviation technologies, fostering innovation in the UTM/ATM domain, and facilitating the creation and management of intricate autonomous flight scenarios.