Aircraft utilization: Average number of block hours per day per aircraft operated.
Available Seat Kilometers (ASK): Number of aircraft seats multiplied by the number of kilometers flown.
Completion fator: Percentage of accomplished flights.
Cost per ASK (CASK): Operating expenses divided by available seat kilometers.
Cost per ASK ex-fuel (CASK ex-fuel): Operating expenses divided by available seat kilometers excluding fuel expenses.
EBITDA: Earnings before interest, taxes, depreciation, and amortization.
Load Factor: Number of passengers as a percentage of number of seats flown (calculated by dividing RPK by ASK).
Revenue Passenger Kilometers (RPK): One-fare paying passenger transported one kilometer. RPK is calculated by multiplying the number of revenue passengers by the number of kilometers flown.
Passenger Revenue per Available Seat Kilometer (PRASK): Passenger revenue divided by available seat kilometers (also equal to load factor multiplied by yield).
Revenue per ASK (RASK): Operating revenue divided by available seat kilometers.
Stage Length: The average number of kilometers flown per flight
Trip Cost: Average cost of each flight calculated by dividing total operating expenses by total number of departures.
Yield: Average amount paid per passenger to fly one kilometer. Usually, yield is calculated as passenger revenue divided by revenue passenger kilometers (RPK).