This paper proposes a mission-driven, dual-biomimetic conceptual design and aerodynamic assessment of a 200 kg-class blended-wing-body unmanned aerial cargo aircraft for regional rapid logistics. The study is motivated by the state of the art in high-efficiency BWB configurations and bio-inspired aerodynamic shaping, where practical deployment is often limited by the coupled challenges of low-speed stall behavior, trim requirements, and insufficient directional stability for tailless BWB platforms. Drawing inspiration from manta rays (smooth wing–body blending and rounded leading-edge characteristics) and eagles (high-aspect-ratio tendency, wingtip devices, and tail-assisted stability augmentation), we establish a traceable mapping from biological traits to engineering geometry features and evaluate their isolated and combined effects. Parameterized geometries are built in CATIA and evaluated using steady RANS CFD (Spalart–Allmaras). A controlled comparative matrix isolates the incremental effects of the biomimetic wing–body planform, leading-edge radius, winglets, V-tail, and surface smoothing, followed by a twin-engine installation assessment that considers nacelle external drag. The results indicate improved cruise efficiency for the biomimetic planform, increased C_(L,max⁡)and delayed stall for the rounded leading edge, marginal net gains from winglets, and a pronounced improvement in static stability and trim requirements with the V-tail, mainly due to interference-driven wing–body pressure redistribution. Surface smoothing provides the largest drag reduction by lowering pressure drag. The final configuration meets the prescribed mission constraints, demonstrating a practical dual-biomimetic design route for cargo BWB UAVs.