In morphing aircraft, flexible skin bears and passes aerodynamic loads when the wing deforms, so the design of the supporting structure applied to flexible skin directly affects the performance of the morphing aircraft. Three types of cellular support structures that can be applied to the flexible telescopic sandwich skin are called V type, U type and trapezoidal shape. By analyzing the in-plane scale properties of these support structures, we obtained the relationship between the in-plane transverse dimensionless equivalent elastic modulus and the three geometric parameters (shape coefficient k, width coefficient t and height coefficient h). The equivalent elastic modulus decreased with the increase of k or h, and increased with the increase of t. We acquired finite element analysis (FEA) results using ANSYS software, and demonstrated the in-plane mechanical characteristics experimentally. Under the same parameters, the in-plane transverse stiffness of the three kinds of structures from large to small were as follows: V type, U type, and trapezoidal shape, indicating that the trapezoidal cellular type had stronger ability to transform and generated the same deformation with less energy. At the same time, we analyzed the stiffness of the three kinds of structures along surface normals with FEA simulation and compared them with the experimental results. Under the same equivalent aerodynamic load along surface normals, normal displacements of the three kinds of structures in decreasing order were trapezoidal shape, U type, and V type, indicating that the structure with better in-plane scalability had weaker load capacity along surface normals. By measuring the maximum normal displacements of the three structures before and after stretching, we showed that the stiffness of each structure type along surface normals improved greatly after drawing. In the case of generating the same normal displacement, the withstand pressure of the structures increased by an average of 30%~60%.