Airport slot allocation is the dominant mechanism for managing capacity at congested airports outside the United States. Current practice is facilitated via expert systems software that apply a complex decision process defined by various criteria, rules and priorities. It is acknowledged that mathematical programming may result in more efficient airport slot schedules. Yet, the incorporation of all the regulations and characteristics of the decision process results in complex mathematical formulations and increased computational times. At the same time, existing models assume that a “slot is a slot” without taking into account the differences in the characteristics and significance of each slot. In this work, through a multi-criteria – multi-stakeholder approach, we introduce a slot valuation index (SVI) that considers the attributes of each airport slot while simultaneously incorporating the preferences of all participating groups of stakeholders. We move beyond the proposal of the SVI by devising a two-stage solution approach that employs the SVI as a relative importance weight in the objective functions of optimisation models. Our approach is able to address additional policy requirements, criteria and slot characteristics while preserving computational tractability.