The Flying-V is a disruptive flying wing aircraft configuration that was realized at the Airbus Future Projects Office (FPO), with research and development continuing at TU Delft. Preliminary findings have indicated that the Flying-V is 25\% more aerodynamically efficient than the state-of-the-art Airbus A350. To further reap the benefits of this configuration, the aerodynamic design of every element of the Outer Mould Line (OML) must be refined to maximize performance during cruise flight. One such element is the wingtip device, specifically the winglet, which are non-planar wings that can significantly reduce the lift-induced drag of an aircraft. For the Flying-V, the winglets also double as vertical stabilizers. A numerical experiment was conducted to evaluate and augment the lateral-directional stability and aerodynamic performance of the Flying-V, incorporating a contemporary winglet design. To enable the winglet’s equally weighted multi-objective optimization, a dedicated module was developed for the existing Flying-V design framework. This module comprises an automated geometry generator, spatial discretizer, flow solver and a differential evolution-based optimizer. For all purposes, the turbulent flow field around the aircraft was resolved using the Reynolds-averaged Navier-Stokes (RANS) model. The Morris method was employed to analyse the sensitivities of the cost functions to the design parameters, yielding an improved baseline design from the ensuing sampling study. The optimization was performed sequentially with complementary planform and airfoil optimization steps. The cruise efficiency of the Flying-V with the initial winglet is found to be lower than the winglet-off case despite portraying strong stability characteristics during approach conditions. While the baseline design’s efficiency is enhanced relative to the winglet-off scenario, the stability performance drops from the initial design. A considerable improvement is obtained in both objectives from the planform optimization process, with the optimizer favouring stability slightly more than efficiency. The airfoil optimization results in a design that is not significantly better than the planform-optimized design in stability and aerodynamic objectives.