There is no official definition for the different categories of flights based on their length, and different sources may use different criteria to define these categories. However, the most common definitions are as follows:

Short-haul flights

Short-haul flights are flights that are relatively short in distance, typically less than 2–3 hours in duration. These flights are often used for domestic or regional travel.

Medium-haul flights

Medium-haul flights are flights that are longer than short-haul flights but shorter than long-haul flights, typically lasting between 3–6 hours. These flights are frequently used for travel within a continent or between neighbouring regions.

Long-haul flights

Long-haul flights are flights that are relatively long in distance, typically lasting more than 6 hours. These flights are frequently used for intercontinental travel between distant regions or continents.

Ulta-long-haul flights

Ultra-long-haul flights are flights that are exceptionally long in distance, typically lasting more than 10–12 hours. These flights are frequently used for travel between distant continents, such as flights between Europe and Australia or North America.

These categories are not fixed and may vary depending on the source and the specific criteria used to define them. Some sources may use different criteria to define the different categories of flights, such as the distance of the flight or the time zone differences between the origin and destination.

Haul flights by organization

Source: https://en.wikipedia.org/wiki/Flight_length