notitur.com August 24, 2026

Airlines

CASK

CASK is the cost to an airline of offering each seat and kilometer. It is the yardstick for a carrier's efficiency and where low cost airlines win their edge over legacy ones. If revenue per seat-kilometer does not beat CASK, every flight subtracts.

Example A low cost with low CASK can sell cheap and still profit where a legacy carrier loses.

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FAQ

What does CASK mean in an airline context?
CASK stands for Cost per Available Seat Kilometer, and it measures how much an airline spends to offer one seat for one kilometer. A low CASK, like 0.05 dollars, indicates high efficiency, typical of low-cost carriers.
How is CASK calculated?
CASK is calculated by dividing total operating costs by the total available seat kilometers. For example, if an airline has costs of 5 million dollars and 100 million seat kilometers, its CASK is 0.05 dollars.
Why is CASK important and how is it different from RASK?
CASK is important because it shows cost efficiency and helps airlines identify savings. It differs from RASK, which measures revenue per seat kilometer, an airline is profitable only if RASK exceeds CASK.

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