The continuing increase in air travel demand combined with the saturation of air traffic networks lead to recurrent congestion episodes. Among the many elements responsible for the escalation of air traffic management costs, we focus particularly on the impact of conflict-resolution strategies that arise in congested networks. In air traffic control, a conflict occurs when two or more aircraft fly too close to one another. While many automated conflict-resolution methods have been proposed, most of them cannot be integrated without a profound revision of traffic control procedures as they lack interaction with air traffic controllers (ATCs). Recently, subliminal speed control has been shown to be a promising approach to reducing the impact of air conflicts onto ATCs' workload and potentially improve airspace capacity. From the perspective of airlines however, little has been done to quantify the impact of conflict-resolution strategies onto direct operating costs. We address this gap by introducing an innovative formulation for the aircraft collision avoidance problem, which integrates the economic profile of flights and promotes equitable solutions. We present a goal programming-based model designed to minimize the deviation from fair solutions during the resolution of potential conflicts. The performance of the model is evaluated using a fuel-equivalent conflict-resolution scheme, hence offering a sustainable framework to efficiently and equitably resolve air conflicts.