What does being "downline" refer to in aviation terminology?

Being "downline" in aviation terminology refers specifically to the concept of an aircraft or crew being away from their home base or domicile. This term is often used to describe the status of a flight, crew members, or aircraft that have traveled away from their originating airport and are now positioned at a different airport or location within the route network.

Understanding this terminology is crucial for flight operations, as it pertains to scheduling, crew rest requirements, and logistical planning for repositioning aircraft or crew deployment. In contrast, the other options do not accurately reflect the meaning of "downline" in this context. For instance, being on time does not relate to a specific location, while being grounded due to weather and being ready for boarding pertain to operational statuses rather than geographical positioning within a route network.