There are 10 fields that contain a blue circle. These fields represent airports or train stations that are connected to each other.
There is a plane flying from LaGuardia Airport in the direction of Newark Liberty International Airport and another plane in the direction John F. Kennedy International Airport. The airports Newark Liberty International and John F. Kennedy International are not on the map.
Fantastic map! This would make an excellent multi-player map. Plenty of choke points, along with Grand Central and the airports for long-distance maneuverability. While playing, I could mentally picture the soldiers fighting street to street.