Flapping wing micro aerial vehicles (MAVs), inspired by biological flight, offer advantages in acoustic stealth, aerodynamic efficiency, and mechanical resilience over rotary-wing platforms. This study presents the design, aerodynamic modeling, and fabrication of a bird-sized flapping-wing UAV. Employing empirical formulations from classical flight dynamics, structural and mechanical configurations were created with advanced design tools. Aerodynamic performance was predicted using quasi-steady blade element theory and advanced computational methods. Simulations confirmed that lift and thrust exceeded vehicle weight and drag, indicating viable sustained flight. The prototype was constructed using lightweight composite materials—carbon fiber for the fuselage and carbon rods with parachute fabric for wings and tail. A three-bar linkage mechanism converted motor input into oscillatory wing motion, with passive spanwise rotation optimizing the angle-of-attack throughout flapping cycles. Ground tests validated the aerodynamic predictions by demonstrating sufficient lift generation. This work provides a foundational platform for future research in bio-inspired MAVs, specifically targeting autonomous surveillance, lightweight propulsion, and low-speed maneuverability. Flutter analysis also identified a critical flutter velocity of approximately 415 m/s.