Method has been used to divide the cost of the whole operation and another administrative that do not directly involved with operation of aircraft. Because it is the essential parts for airline manager to manage these cost in order for airline to acknowledge what cost them the most and how can they deduct the cost if any way possible. Also very important that each cost must be categorized in their own field. Otherwise the calculation can be misleading and confusing. Furthermore cost must be categorized with fixed direct operating cost or variable direct cost for direct operating cost.