Here is an example of a real world flight plan-
In this flight plan, VOMM/25 and VABB/27 are the origin and destination airports and runways respectively.
DOHIA and MOLGO1A are the SID and STAR and the other words (DORAM and AGELA) are waypoints.
However, the B466 given in the FPL is called an Airway.
Airway routing occurs along pre-defined pathways called flight paths. Airways can be thought of as three-dimensional highways for aircraft. In most land areas of the world, aircraft are required to fly airways between the departure and destination airports. The rules governing airway routing cover altitude, airspeed, and requirements for entering and leaving the airway. Most airways are eight nautical miles (14 kilometers) wide, and the airway flight levels keep aircraft separated by at least 1000 vertical feet from aircraft on the flight level above and below. Airways usually intersect at Navaids, which designate the allowed points for changing from one airway to another. Airways have names consisting of one or more letters followed by one or more digits (e.g., B466 or UA419)
I noticed that this feature is missing in Infinite Flight, and thus complicates the process of making a real-world FPL for flights. This would be a very useful feature in addition to the SIDs and STARs feature which already exists.
(In order to prevent clogging up the map, my suggestion is that airways can be input into the flight plan only when you manually search for it.)