In December an Air Force/Navy Armed Reconnaissance Coordinating Committee established a system to assist the command and control of air operations over North Vietnam by dividing the country into geographical regions and assigning them to one or other of the air services.  Prior to this time air operations over North Vietnam during the Rolling Thunder campaign were conducted by the Air Force and the Navy in alternate three-hour intervals which led to some chaotic situations.  In the early days there was not even much coordination between individual units and it was not unheard of for aircraft from two different Navy aircraft carriers to attack targets in the same area without knowing of each other’s operations until they arrived over the target.  The system devised in November 1965 divided North Vietnam into seven Route Packages or Route Packs.  Immediately north of the DMZ was Route Pack I and the other packs extended northwards in sequence.  Route Package VI was subdivided in VIA to the north and west of Hanoi and VIB to the south and east of the city, the dividing line running along the main railway line to China.  Initially, the Air Force and Navy operated in all Route Packages at assigned times, alternating Packages every six weeks.  However, in April 1966 operations within the Route Packages were more strictly divided with the Air Force being assigned to operations in Route Packages 1, 5 and 6A and the Navy being assigned to Route Packages 2, 3, 4 and 6B.  Although the Route Packages were allocated at CINCPAC level, in actual operations the Services frequently crossed boundaries if necessary.