Existing analyses, based on numerical inferences for the alternatives, have not provided conclusive results. The authorsx2019; approach used specific case studies and the inclusion of multiple decision makers in the evaluation. With help of THOR, a multicriteria decision support system under development at COPPE/UFRJ and CASNAV, a consistent hierarchy of the possible alternatives was achieved. This paper describes the methodology used to input data and decision-makersx2019; preferences in the decision support system.