Airport employees often account for a substantial share of daily airport access trips, yet current planning for airport landside access in the United States focuses almost exclusively on identifying and addressing the needs of air passengers. Airport worker travel patterns are normally studied by using the standard journey-to-work components of travel demand models and generally do not capture the unique factors affecting this group's commuting behavior. The Port Authority Trans-Hudson (PATH) commissioned a preliminary study evaluating the economic feasibility of extending PATH rail service to Newark Liberty International Airport, New Jersey. An empirical analysis of survey data collected during this effort suggests that the traditional travel demand model approaches to studying airport worker commuting patterns often mischaracterize the travel patterns and attitudes of a large airport access market segment. This research finds that the omission of airport worker input in the planning process is likely to result in the overestimation of public transit demand and may only exacerbate the optimism bias that has typically affected rail transportation investments in the United States.