Fixed-wing aircraft are particularly attractive for Mars surface exploration, but Martian low-density atmosphere poses several issues to airfoil aerodynamic design. In this framework, the paper deals with an optimization procedure aimed at maximize the aerodynamic efficiency of Low-Reynolds airfoils. The design procedure embeds airfoil parameterization, aerodynamic computation, and optimization algorithm for a maximum efficiency objective at Re∞=2×105 and Re∞=3.4×104. Two airfoil parameterization models are developed and adopted within the design optimization. The XFoil solver is considered to address airfoil aerodynamics; while its optimal shape is generated with a genetic algorithm to simulate a cruising condition. Design optimization developed two different airfoils with (L/D)max=10.4 and 16.4, achieved at Re∞=3.4×104. Aerodynamic performances of these wing sections are discussed in the work. Optimal airfoils pointed out that maximization of aerodynamic efficiency is associated to both a thickness reduction and a curvature increase of the aeroshape. Finally, aerodynamics of the optimal airfoils are also investigated with computational fluid dynamics simulations.