Where it connects

Abstract

With the rise of digitization and the increasing emphasis on sustainability, future mobility systems are expected to rely more on multimodal journeys, where various transport modes are combined into a seamless travel experience. This approach shifts the focus from individual transport modes to the overall passenger experience. In the air transport sector, air&rail integration exemplifies such multimodal journeys, providing opportunities to reduce congestion at airport hubs, enhance airports’ competitive position, and promote more sustainable mobility. However, achieving seamless multimodal travel at airports is a challenge due to the integration of separate transport systems into a cohesive network.

Research goal 
This dissertation investigated the integration of transport modes at airport hubs to improve passenger-oriented multimodal air journeys and offers insights for practitioners in the mobility sector, designers, and researchers, to design connections between transport modes. The following research questions guided the study:
1. What are the properties of a passenger-oriented multimodal air journey?
2. What influences the effective delivery of a passenger-oriented multimodal air journey?
3. What tensions arise when stakeholders engage in the (co-)creation of integrated multimodal air journeys, and how can these be mitigated?

Methodology
A qualitative Action Research approach was employed, beginning with a preliminary exploration of the context and purpose, followed by three iterative and reflective research cycles. This method facilitated an in-depth understanding of how passenger-oriented multimodal air journeys are developed and delivered in practice, as well as the identification of opportunities for improvement. In each research cycle, the primary researcher engaged at different levels: starting with reflections on personal experiences and assumptions through first-person practice, moving to interviews with field experts via second-person practice, and finally examining dynamics within the system related to the researched air&rail case from a third-person practice. The research focused on the integration of passenger-oriented multimodal air travel, using air&rail as the primary case, with each research cycle conducted in a comparable European context involving different participants and data sources.

Context & purpose
The Action Research began with a literature review and an embedded field study within an airport organization to understand real-world practices. This exploration led to three guiding principles: prioritizing the passenger experience, adopting a systems perspective to address the complexity of multimodal integration, and providing actionable recommendations for
practice. These principles proved to be essential in both the literature and practice for understanding and improving multimodal air travel and shaped the remainder of the study.

Research cycle 1
The first research cycle aimed to better understand the travel phases involved in multimodal air journeys, the factors influencing the passenger experience, and the role of airports in facilitating these journeys. Through autoethnography, the research cycle reflected on the travel experiences of both researchers and practitioners. The study identified eight key integration factors: journey explanation and preparation, personalized and proactive assistance, wayfinding, proximity of modalities and facilities, multimodal transfer services, balanced transfer time, waiting environments, and in-travel comfort. The findings show that multimodal air journeys cannot be treated as separate segments but must be designed as a seamless whole. From the passenger’s perspective, each transfer between modes represents a system boundary crossing, setting multimodal travel apart from single-mode journeys. This highlights the need for close collaboration between transport systems to place the passenger experience at the center of multimodal air travel.


Research cycle 2
The second research cycle aimed to enhance the understanding of delivering passenger-oriented multimodal air journeys by interviewing transport and airport hub operators. This research cycle employed service blueprinting to analyze the processes that support the delivery of these journeys. The research identified five key factors influencing passenger experience: integrated
booking systems, whole journey guidance, transfer time and ease, baggage management, and disruption management. An important insight was that the passenger experience already starts before departure, making pre-journey factors such as booking systems and journey preparation essential. To ensure that these factors are perceived in a positive way by travelers, processes – such as IT, infrastructure, scheduling, operations, commercial activities, inter-organizational activities, and strategic efforts – and external conditions – like market dynamics and regulations – should be aligned. The study further indicate that airlines often lead in shaping multimodal air journeys, through the “baseline modality” concept, which tends to implicitly set standards and
shaping passenger expectations. Progress towards multimodal air journeys is hindered by delivery mechanisms that fragment responsibilities and goals among operators, and perpetuate competition in the market. Successful multimodal air transport delivery relies on collaboration within and across systems and regulations that promote integration.

Research cycle 3
In the third research cycle, interviews and co-creation activities were used to explore how stakeholders experience and shape the integration of air&rail transport in practice. The research identified six system-level tensions that emerged during co-creation: no control over airport slots, conflicting priorities in train stop allocation, misaligned scheduling, different business models, fragmented booking systems, and different passenger experiences. Additionally, three collaboration-level tensions were observed: limited mutual understanding, challenges in applying systems thinking within organizations, and differences in organizational momentum. These tensions extend beyond collaboration among individual partners and demonstrate the need for an orchestrator in decision-making, as well as for a European governing body to establish a supportive regulatory framework.


Conclusions
This research demonstrated that integrating transport modes with aviation necessitates a fundamental redefinition of the airport as a multimodal transport hub, where the airport is not seen merely as a physical junction but as a strategic actor in multimodality. At these hubs, various boundaries converge: between modalities, organizations, countries, and regulations, as well as within the transport systems themselves. These multiple boundaries explain why multimodal ecosystems are likely to stagnate. Furthermore, the research found that the baseline modality concept often steers passenger expectations toward a dominant modality (often the flight segment). As long as passengers base their experience on one (the dominant) modality, fragmentation in passenger experiences is likely to persist. The baseline modality also emerges in the delivery and development of multimodal air journeys. Airlines play a dominant role in this process, exerting significant influence on the design of the multimodal journey. This gives rise to a paradox: insufficient coordination between transport systems can undermine the performance of the overall multimodal system, while passengers may simultaneously benefit from certain services provided by the air transport system throughout the entire journey.
Successful multimodal integration requires collaboration among various transport systems, joint decision-making with diverse stakeholders, and regulatory frameworks that are both flexible and supportive, all facilitated by effective orchestration. The transition to multimodal air transport largely depends on reconfiguring existing structures. This process is driven by collaboration, design practices, and experiential learning, where knowledge and practices are reshaped through open and shared innovation processes.

Future research and recommendations
The thesis outlined future research opportunities, such as exploring other contexts, diversifying participant groups, further developing key concepts, applying design interventions in transport, and studying the impact of digitalization on mobility. It concludes with action-oriented recommendations.
Operators should focus on ensuring clear communication, coordinated information, trained staff, consistent service quality, direct airport connections, aligned timetables, interoperable systems, simplified baggage handling, and brand-integrated partnerships.
Airports and other hubs can support multimodal air journeys by training staff, providing clear signage, ensuring efficient transfer infrastructure, streamlining processes, and offering comfortable waiting areas for each mode of transport.
Governments can enhance multimodal air travel by supporting reliable rail systems, offering financial incentives to stakeholders, facilitating negotiations, and ensuring viable business models for operator alliances.
Finally, the thesis emphasizes that successful multimodal air integration requires collaboration among stakeholders built on experiential learning (such as going on field studies), long-term internal anchoring of insights, and continuity in participation to ensure understanding and trust.