Airplanes are a fast but expensive means of shipping goods, a fact which has implications for comparative advantage. The paper develops a Ricardian model with a continuum of goods which vary by weight and hence transport cost. Comparative advantage depends on relative air and surface transport...

The core subjects of trade theory are the pattern and volume of trade: which goods are traded by which countries, and how much of those goods are traded. The first part of the paper discusses evidence on comparative advantage, with an emphasis on carefully connecting theory models to data...

In the last quarter century, wage inequality has increased dramatically in the United States. At the same time, the US has become more integrated into the world economy prices of final goods have changed, the capital stock has more than doubled has become steadily more educated. This paper...