The U.S. opportunity cost of 1 bundle of auto parts in terms of airplanes is 2: for every additional bundle of auto parts, 2 airplanes must be forgone. The Mexican opportunity cost of 1 bundle of auto parts in terms of airplanes is ½: for every additional bundle of auto parts, only ½ of an airplane must be forgone. Because the opportunity cost is lower, the United States has a comparative advantage in airplane production, and Mexico has a comparative advantage in auto parts production. In autarky, each country is forced to consume only what it produces: 1,000 airplanes and 500 bundles of auto parts for the United States; 500 airplanes and 1,000 bundles of auto parts for Mexico.