“…Much effort has been put into developing advanced traffic flow management techniques. [59,63,16,47,65,14,56,57] Currently, Traffic Management Coordinators (TMCs) monitor congested traffic situations using flight data from the Enhanced Traffic Management System (ETMS) and restrict incoming traffic flows into the sector, if necessary. The restrictions on incoming traffic flows can be implemented either by changing the arrival times of incoming aircraft, which is called metering, or imposing the proper distances between aircraft, which is called spacing.…”