Generally sandwich structure is used for wings, tail, fuselage, speed brake, engine compartment, etc. Compared with thin-walled skins, sandwich panels have a much larger thickness, strong resistance to instability, smooth surface, and good aerodynamic appearance. However, due to the complex manufacturing process and the difficult inspection of process quality, the application is greatly restricted. The materials of the sandwich structure sheet mainly include aluminum alloy, stainless steel, titanium alloy and various composite materials. Interlayer materials include light wood, foam plastic, etc., and metal or composite materials can also be used to make corrugated interlayer or honeycomb interlayer. The interlayer and the surface board are generally glued together, or they can be welded to form a whole.