We focus on the passenger as the key stakeholder of the Air Traffic Management (ATM) system. Air transport is only a portion of the passenger door-to-door journey, which also relies on other modes of transportation (a taxi ride, bus ride, drive over the freeways, rail, or other) to complete the journey. Transportation modes are usually studied separately as if not interacting, although they are intrinsically coupled through passenger transfers; in fact, the failure of one mode disrupts the entire passenger journey. In this effort, we gather specific passenger location data from individual passengers and aggregate data on passengers, both airside (within the terminal) and landside (within the airport and outside the airport) to build a better estimate for the expected time of departure for an aircraft at an airport gate. The system is composed of multiple technologies that either access specific data or aggregate data of passengers. A "push" technology is used to shape passenger behavior by informing the passenger about security delays, traffic delays, and other information that could encourage the passenger to be on time to the departure gate.