The 8th International Conference on HCI in Mobility, Transport, and Automotive Systems, MobiTAS 2026, held as part of the 28th HCI International Conference, HCII 2026, took place in Montreal, QC, Canada, during July 2026.A total of 7435 individuals from academia, research institutes, industry, and government agencies from 94 countries submitted contributions to HCII 2026. Following peer review, 1463 papers and 360 posters (as short research papers) are included in the volumes of the HCII 2026 proceedings published just before the start of the conference.Two volumes (LNCS 16741 and 16742) of the HCII 2026 proceedings are dedicated to this year’s edition of the MobiTas Affiliated Conference focusing on topics related to:HCI in Mobility, Transport and Automotive Systems (Part I): Autonomous Driving, Decision-Making, and Human–AI Interaction; In-Vehicle Interaction, UX, and Smart Interfaces; Simulation, Virtual Environments, and Prototyping for MobilityHCI in Mobility, Transport and Automotive Systems (Part II): Aviation Systems and Pilot Interaction; Urban and Inclusive Mobility; Safety, Trust, and Risk Mitigation in Aviation and Automotive