A large literature has shown that geographic frictions reduce trade, but has not clarified precisely why. We provide insights into why such frictions matter by examining which parts of trade these frictions reduce most. Using data that tracks manufacturers' shipments within the United States on...

A large and growing share of international trade is carried on airplanes. Air cargo is many times more expensive than maritime transport but arrives in destination markets much faster. We model firms' choice between exporting goods using fast but expensive air cargo and slow but cheap ocean...

Wolf (2000) demonstrates that trade within the U.S. appears substantially impeded by state borders. We revisit this finding with improved data. We show that much intra-national home bias can be explained by wholesaling activity. Shipments by wholesalers are much more localized within states than...

We show that 'home bias' in trade patterns will arise endogenously due to the co-location decisions of intermediate and final goods producers. Our model identifies four implications of home bias arising out of specialized industrial demands. Regions absorb different bundles of goods. Buyers and...

Purchasing goods from distant locations introduces a significant lag between when a product is shipped and when it arrives. This is problematic for firms facing volatile demand, who must place orders before knowing the resolution of demand uncertainty. We provide a model in which airplanes bring...

We examine a generalized version of Flam and Helpman’s (1987) model of vertical differentiation that maps cross-country differences in income distributions to variations in import variety and price distributions. The theoretical predictions are examined and confirmed using micro data on...