The Sovereign was developed based on the 2022 aircraft, Leviathan. Designed for a higher payload capacity, the Sovereign features optimized aerodynamics and reduced manufacturing complexity compared to its predecessor. The aircraft implements a targeting pod to house avionics and telemetry systems. The Sovereign has a significantly improved PADA (Powered Autonomous Delivery Aircraft) design and a reduced size GTV (Ground Transportation Vehicle) compared to the predecessors. Overall, the 2023 aircraft Sovereign takes the proven Leviathan platform and enhances it in several key areas to create a more capable next-generation aircraft. The aircraft placed 3rd overall in the 2023 SAE Aero Design West.

The 2022 aircraft Leviathan was the first design under new competition rules, consisting of three vehicles: the main aircraft, the PADA (Powered Autonomous Delivery Aircraft), and the GTV (Ground Transportation Vehicle). With the payload of waterbags, loading configuration was straightforward. The fuselage optimized for simplified manufacturing using plywood sheets over composite monocoque skins. Despite the design simplifications, the aircraft placed 7th in the highly competitive 2022 SAE Aero Design East competition. The lessons learned from this initial foray will be invaluable for future iterations aimed at an even lighter yet stronger airframe, enhanced payload capacity, and improved flight dynamics to achieve a higher ranking next year.

The 2021 aircraft was to optimize structural weight by using composite monocoque skin and tubes that was used to create the fuselage. This enabled the fuselage to be lightweight and have a high payload capacity. Similarly, the nerf bombs were oriented in a criss-cross orientation to allow for optimal payload capacity and ease of deployment during the operation. The fuselage configuration and cross-sectional area were chosen to accommodate the unique payload orientation. This aircraft placed 5th in the 2021 SAE Aero competition.

The 2020 aircraft is the first attempt at the advanced class. In order to reduce structural weight and overall aircraft size, despite the high volume of payload, RAD has employed a composite monocoque fuselage construction. This enables a high degree of strength and stiffness to be retained, while still remaining lightweight and minimizing non-payload volume within the outer mold line of the aircraft. 

This aircraft was designed to maximize the number of "passengers" on board. Using tennis balls to simulate passengers, and steel plates to simulate cargo, the 2019 aircraft was able to lift a total of 62 passengers with a 0.5 lb per passenger cargo. The aircraft is unique in its blended-wing body design that gives it a manta ray shape. This aircraft placed 27th at the SAE Aero Design West 2019 Regular Class competition. 

The 2018 aircraft boasts an improved aerodynamic design. Using various manufacturing strategies and materials, RAD created an aircraft with a high lift-to-drag ratio. The aircraft holds a total of 26 passengers with a 0.51 lb per passenger cargo ratio. This aircraft placed 6th overall at the SAE Aero Design West 2018 Regular Class competition.