“…The first can be categorized as preexisting conditions, whereas the second can be categorized as the air traffic control (ATC) response to those preexisting conditions. The difference between these two types is that different measures can be taken to counter the same set of preexisting conditions, or interdependencies, as illustrated by the metroplex-site survey findings [5,[8][9][10][11]. For example, when the proximity of airports causes interactions between traffic flows to and from different airports, traffic flows may be laterally segregated at one location, e.g., the segregation of Fort Lauderdale-Hollywood International Airport (FLL) and Miami International Airport (MIA) flows in the Miami terminal radar approach control (TRACON); whereas traffic flows at another location may involve traffic at one airport being stopped or requiring prior approval before being released for departure, e.g., departures from LaGuardia Airport (LGA) and Newark International Airport (EWR) merging over the ELIOT fix in N90.…”