The use of dynamic simulation to model the landside facilities of a modern airport offers a valuable analytical tool to the airport decision maker. Simulation technology can test and rank investment proposals by providing specific projections relating to landside congestion. This paper discusses an operating simulation that models the behavior of persons and vehicles moving through the landside systems. The output of the simulation is statistical information regarding the congestion parameters of waiting time, occupancy and flow at landside facilities. A description of how simulation outputs are validated and used in the determination of landside capacity is also included.