identifying a possible pair of aircraft from a database of aircraft flight plans, the possible pair of aircraft including a leader aircraft and a follower aircraft, each aircraft having an initial flight plan;

providing a new flight plan for the leader aircraft by modifying the initial flight plan of the leader aircraft;

providing a new flight plan for the follower aircraft by modifying the initial flight plan of the follower aircraft, wherein the new flight plan of the follower aircraft includes a common ground section which overlaps with the new flight plan of the leader aircraft so that the follower aircraft flies in an upwash region of wake vortices of the leader aircraft;

determining when there is a net trip fuel savings associated with the possible pair of aircraft based on the leader aircraft utilizing the new flight plan and the follower aircraft utilizing the new flight plan instead of using the initial flight plans by continuously applying a criteria between a merge point and a split point, the merge point representing an initial waypoint in the common ground section and the split point representing a final waypoint in the common ground section, wherein the criteria comprise continuously comparing the speed envelope of the leader aircraft with the speed envelope of the follower aircraft making sure that any given Mach number and altitude the leader aircraft and the follower aircraft fly at together is compatible with their respective flyable domains of speed and altitude;

when there is a net trip fuel savings and when the second criteria is satisfied, replacing the initial flight plans of both the leader aircraft and the follower aircraft in the database with the new flight plans;

flying the leader aircraft along the new flight plan of the leader aircraft; and,

flying the follower aircraft along the new flight plan of the follower aircraft.