An automated, real-time decision support system for reassigning, rescheduling, and rerouting aircraft in response to flight operation disruptions, in which sets of optimal solutions are provided through use of evaluation statistics to assist operations management in selecting the optimal solution best conforming to operational constraints and user requirements. Solutions are generated through the execution of unary operations, binary operations, three-way operations, and reverse binary operations on grounded aircraft routes, available aircraft routes, and phantom routes which implicitly cancelled flights. Solutions are evaluated for feasibility with respect to operations constraints and user requirements. Marginal value calculators are used to differentiate feasible solutions and identify optimal solutions. The marginal value calculators are dynamic, hierarchical calculators that permit use of multiple, prioritized, and weighted route and operation attributes in comparing solution values. Marginal value calculators are selected by means of a decision tree.