What Is ASK? Definition & Meaning in Aviation
ASK (available seat kilometres) is a measure of an airline’s capacity: the number of seats multiplied by the distance flown in kilometres.
In plain language
One seat flown for one kilometre equals one ASK. It lets airlines compare capacity across routes of different lengths.
Example
An aircraft with 150 seats flying 1,000 km provides 150,000 ASK.
Why it matters
ASK is the standard way to compare how much capacity different airlines offer, whatever the route length. Together with RPK, it shows whether airlines are growing and how full they are.