New aluminum alloys for aircraft structures have been introduced recently. These new alloys are designed in such a way as to improve the weight efficiency of the structure. A good understanding of the loading of the different airframe parts is needed for this purpose. The present paper focuses on the micro-mechanical models which are used, or will be used, to find the optimum property balance. These models are based on microstructural features, which can be measured on the material or modeled by physical metallurgy equations. Examples are given for the typical rolled products used for the fabrication of an aircraft : thin sheets for fuselage application and plates for spars and ribs.