Dynamics of water droplets of various size in the vicinity of the leading edge of an airfoil is investigated. Bending of drop trajectories (and, consequently, the extention of a wetted wing surface) is shown to depend significantly on the drop deformation and Saffman force, arising in the boundary layer. (Influence of a “near-surface force” caused by the “drop imaginary reflection” is far less). A maximum in the dependence of wetted surface extention on the initial drop radius is revealed. Hence, air viscosity, drop deformation and its break-down in front of a flying apparatus are really important for the following icing process.