X
The flight ID i.e. MOM is input by the crew into the FMS. What we see as a flight ID is what the crew or the ops department enter and is broadcast by the aircraft.
Regarding the VIR flight ID, I dont know the significance but it is the alpha-numeric ID used by the airline for the flight.
Some airlines use the same flight ID for more than one route. United Airlines domestic flights are good example using the same flight ID for 2 or 3 different routes per week, nightmare stuff. Some cargo flights operate with the same flight number on diferent routing dependent on the day of the week
The majority of the routes on the server have been provided by a automatic routine on the server and quite often its has been wrong, i.e getting the org/dest the wrong way round, showing only partial routes when there is a via in the routing and just plain wromg etc, hence the reason I took it on myself to update the route data.
Alan