In what situation might a flight be categorized as a "no-op"?

A flight is categorized as a "no-op" when it has been cancelled and will not operate. This terminology is used to describe a situation in which there is no operation of the flight at all, meaning that passengers will not board the aircraft, and it will not take off or land as scheduled.

In scenarios like a flight delay due to weather, the flight may still take off once conditions improve, so it remains an operation, albeit delayed. Similarly, if a flight is rerouted to a different city, it is still considered operational, as it is actively serving a modified route. An overbooked flight that continues to operate, despite the number of passengers exceeding the seats available, also does not qualify as a "no-op" because it is still running and carrying passengers.

Thus, when a flight is officially cancelled, it ceases to operate entirely, which aligns perfectly with the definition of a "no-op".