Speed and cost-effectiveness are increasingly required in responding to new property goals for airframe alloys. Moreover, motivated in part by competition from alternative materials, property goals for aluminum alloys in airframes are ever higher. In order to help meet these two challenges, physically-based computer modeling approaches have been developed, enabling both reduced testing matrices during alloy development and quantitative predictions of key properties as a function of alloy composition and processing. Significant reductions in alloy development lead times can be achieved if all experimental alloys are already optimized with respect to their position in the phase diagram, i.e. contain as much total solute as needed or possible whilst remaining solutionizable. Based on the knowledge of the phase diagram of Al-based alloys that has been acquired by the aluminum community over the years, a PC-based software package designated Prophase has been developed to calculate amongst other things such optimum compositions. Examples of the use of this software in airframe alloy development will be presented. Other applications of the approach, including modeling of sensitivity to weld cracking, will also be discussed.