What is a line holder in the context of flight crew members?

In the context of flight crew members, a line holder refers to a crewmember who has been awarded a line of flying time, which is essentially a schedule of flights they are responsible for operating. This schedule is typically set in advance and can include a series of flights over a specific time period, reflecting the crewmember's consistent assignment within their airline or flight department. Line holders usually have more predictable schedules compared to reserve crewmembers, who must remain available for assignment as needed.

Other choices reflect different roles or states of being within the flight crew structure but do not accurately define what a line holder is. For example, some may be assigned to a specific aircraft or have flexible schedules, but those terms describe arrangements and flexibility rather than the specific assignment of a flight schedule associated with being a line holder.