The given problem is proposed:
World Airlines is thinking of buying a new plane for its shuttle service. Why does the economist's notion of cost suggest that World Airlines should consider the plane's price in deciding whether it is a profitable investment but that, once bought, the plane's price is not directly relevant to the airline's profit-maximizing decisions? In such a case of "sunk costs," which cost should be used for deciding where to use the plane?
Here is my answer:
The price of the airplane best expresses the opportunity cost, or the cost of goods that were given up to produce the airplane. World Airline's profit-maximizing decisions should be based on economic cost, or the cost required to keep the plane in its present use. In the case of "sunk costs," implicit cost or rather, the rental rate (v) should be used for deciding where to use the plane.
Am I on the correct track? Is my answer too general?