Aerodynamics optimization of airfoil for flying-wing type Mars airplane is conducted to show tradeoff between maximization of aerodynamic performance and stability requirement. To see the tradeoff between the two objectives, a multiobjective evolutionary algorithm is used where aerodynamic performance of each airfoil is evaluated with a two-dimensional laminar Navier-Stokes flow solver. Some design constraints are applied to obtain feasible airfoil shapes. The obtained Pareto-optimal airfoils show tradeoff between the two design objectives. Analysis of the flow field of the obtained airfoils leads to some useful knowledge in designing airfoil for flying-wing type Mars airplane.