This paper presents a case study of a multicriteria supplier development problem in the aerospace Mexican industry, implementing an aggregation/disaggregation approach to construct a fuzzy outranking relation model as consistent as possible with holistic preferences expressed by the decision-maker (DM). An analysis with twelve real suppliers was carried out with this approach showing consistency between the model and the preferences. The Preference Disaggregation Analysis is embedded in a genetic algorithm to support the multicriteria decision aid process.