I have wondered several times about this and now seeing this question Can two different planes share the same flight number? I decided to ask:
In general in our mind we think of flights number as something unique (at least I did). An ID. Often journalists mention the flight number when they want to refer to a particular event (a crash, a forced landing, whatever) which reinforces the idea of uniqueness.
From what I read a flight number:
- clearly does not represent a plane
- does not represent a unique flight in particular (since the same flight number is commonly reused several times to represent the same flight at the same time in different days)
- does not represent a route (since the flight number can be used on several routes)
What is its use than and does it represent? What makes it unique and usable? can there be, for instance, the same flight number at the same time in different routes?