A system for managing an air mission plan intended to be run by a plurality of platforms performing a plurality of tasks, the system comprising: - an input interface, for users, of the objectives and constraints of the mission; - an acquisition interface of operational states of the platforms performing the mission tasks and acquiring tactical environment data around the platforms; - a mission computation engine, suitable for determining a mission plan comprising a list of tasks to be performed in order to fulfill the mission objectives while respecting the constraints thereof; - at least one display (42, 43) and one display management assembly on the display (42, 43), suitable for displaying, on the display (42, 43), at least one summary window (46, 48) comprising information representative of tasks of a mission plan established on the basis of a current mission context; the input interface and/or the acquisition interface is able to be activated to define at least one new mission context comprising at least one objective, a constraint, an operational state and/or a tactical environment different from an objective, a constraint, an operational state and/or a tactical environment, respectively, of the current mission context, characterized in that the mission computation engine is able to determine a mission plan comprising an allocation of tasks between the platforms by taking account of the operational state of the platforms and the tactical environment around the platforms, the mission plan computed by the mission computation engine comprising, for each platform, a sequenced list of tasks which the platform must perform, associated with a flight plan for the platform; the mission computation engine being able to be activated to determine a new mission plan based on the new mission context defined by the input interface and/or by the acquisition interface, the display management assembly being able to display, on the summary window (46, 48), information representative of tasks of at least one new mission plan obtained by the computation engine based on the new mission context defined by the input interface and/or by the acquisition interface. - an input interface, for users, of the objectives and constraints of the mission; - an acquisition interface of operational states of the platforms performing the mission tasks and acquiring tactical environment data around the platforms; - a mission computation engine, suitable for determining a mission plan comprising a list of tasks to be performed in order to fulfill the mission objectives while respecting the constraints thereof; - at least one display (42, 43) and one display management assembly on the display (42, 43), suitable for displaying, on the display (42, 43), at least one summary window (46, 48) comprising information representative of tasks of a mission plan established on the basis of a current mission context; the input interface and/or the acquisition interface is able to be activated to define at least one new mission context comprising at least one objective, a constraint, an operational state and/or a tactical environment different from an objective, a constraint, an operational state and/or a tactical environment, respectively, of the current mission context, characterized in that the mission computation engine is able to determine a mission plan comprising an allocation of tasks between the platforms by taking account of the operational state of the platforms and the tactical environment around the platforms, the mission plan computed by the mission computation engine comprising, for each platform, a sequenced list of tasks which the platform must perform, associated with a flight plan for the platform; the mission computation engine being able to be activated to determine a new mission plan based on the new mission context defined by the input interface and/or by the acquisition interface, the display management assembly being able to display, on the summary window (46, 48), information representative of tasks of at least one new mission plan obtained by the computation engine based on the new mission context defined by the input interface and/or by the acquisition interface.