An iterative method for solving the inverse/mixed problem for a multi-element airfoil at low speeds in the framework of the Reynolds averaged Navier–Stokes (RANS) equations, which belongs to the class of residual correction methods, is developed. The deformation of the surface of the airfoil elements, decreasing the residual between calculated and target pressure distribution, is determined using the panel method for solving the direct/inverse problem for the same airfoil in an incompressible inviscid flow. A brief description of the methods used is given. Examples of constructing the geometry of the elements of a multi-element airfoil according to a given pressure distribution are shown, demonstrating high rate of convergence of the method (3–4 iterations). High-lift thick ( ) laminar airfoil with cruise flap is designed for use in the wing of low-speed aircraft. The wing with this airfoil was tested on a thematic model in the wind tunnel. High values of lift are obtained with a moderate level of profile drag.