AC#4  ,     477  ,     "Boeing 737-400 Paint1"
    |............|........................|
Aircraft......Cruise...........Aircraft title
 tag..........speed

Aircraft tag:
This is used strictly by the compiler. Aircraft are referenced by this tag in the flight plan file, so for example if tag AC#4 is specified in a flight plan there must be a corresponding aircraft tagged AC#4 in this list. You can add any tag numbers you want, as long they are prefixed by "AC#" and are not already used. The number must be less than 65536. The same aircraft can be referenced in different sets of source files and they do not have to use the same number.

Cruise speed:
This is the cruise speed (TAS) given in the aircraft specifications. It can be found in aircraft manuals or other reference material. Note that this number does not determine the actual cruise speed of AI aircraft, that is based on a cruise speed parameter included in the aircraft model’s aircraft.cfg file. This number is used only by the compiler to compute the trip time for the flight so it can come up with arrival times and sector mapping for flight plans that don’t use fixed arrival times.

Aircraft title:
This is how FS2002 finds an aircraft model when it wants to make it appear as AI. This title must exactly match a title in the aircraft.cfg file for one of the installed aircraft. It will appear in a line such as title = Boeing 737-400 Paint1. Note that each aircraft can have several different ‘skins’, hence the Paint1, Paint2, etc. suffixes. Each of these will have separate title lines in the same aircraft.cfg file. These different paint schemes often represent different airlines.