Abstract: A real-time multimodal travel estimation and routing system having a first mode for air-based travel and a second mode for ground-based travel, and a method for estimating a time of arrival to a ground-based destination having a first mode for air-based travel and a second mode for ground-based travel is disclosed. The real-time multimodal travel estimation and routing system is configured to receive an input designating a ground-based destination, a request for an available ground-based travel option, and display an estimated time of arrival to the ground-based destination based on first data stored on-board the aircraft for the second mode and real-time flight information for the aircraft for the first mode. The system is further configured to receive an update of real-time information for the available ground-based travel option and update the first data stored on-board the aircraft.