Tax Expenditures for Owner-Occupied Housing: Deductions for Property Taxes and Mortgage Interest and the Exclusion of Imputed Rental Income by James Poterba and Todd Sinai. Published in volume 98, issue 2, pages 84-89 of American Economic Review, May 2008

We examine two factors that explain air traffic congestion: network benefits due to hubbing and congestion externalities. While both factors impact congestion, we find that the hubbing effect dominates empirically. Hub carriers incur most of the additional travel time from hubbing, primarily because they cluster their flights in short time spans to provide passengers as many potential connections as possible with a minimum of waiting time. Non-hub flights at the same hub airports operate with minimal additional travel time. These results suggest that an optimal congestion tax might have a relatively small impact on flight patterns at hub airports.

Consumption commitments—goods like housing for which adjustment is costly—change the relationship between risk and consumption. Commitment provides a motive to reduce consumption when possible future losses are too small to warrant adjustment but not when losses are large enough that adjustment would be worthwhile. This implies conditions under which mean-preserving increases in risk can increase housing consumption. Our empirical evidence exploits the interaction of these conditions with a novel proxy for unemployment risk: couples sharing an occupation. Consistent with our model, same-occupation couples consume more housing only when adjustment costs are high and potential losses are sufficiently large.