A.s.k.
 

I have just been reading a business school case study that compared airline costs and revenue per "available seat kilometre".

What does "available" mean in this context?

This means the actual capacity in terms of number of seats available times distance flown as opposed to the Revenue Passenger Kilometres (RPK) which is the actual number of seats sold times distance flown.

Thanks, I'd never heard the expression revenue seat kilometers and I couldn't understand why they didn't just say 'seat kilometers'.