Abstract. In this paper, we present a graphical decision support tool to aid in analyzing the U. S. Transport network. In addition to displaying ordinary statistics, our tool can calculate the expected minimum-delay route for a given origin and destination airport. Our solution algorithm uses Monte Carlo simulation to solve the corresponding shortest path problem with correlated random costs. Of particular novelty in our approach is the air network sampling that we use in order to accurately determine the cascading effect of delays on flights. Our statistical models and simulations are based on real flight data obtained from the U.S. Department of Transportation.