Integrating air transport with alternative modes of transport holds great promise for substituting short-distance flights in regions like Europe, provided that the benefits of existing transport networks are preserved. Effective multimodal integration requires collaboration among transport operators and hubs to enhance the passenger experience. This study explored the perspectives of these practitioners across Europe through an interview-based case study, identifying key factors for a passenger-oriented multimodal air journey and examining the mechanisms that influence their delivery. The findings reveal five Passenger Experience Factors (PEFs) that contribute to a successful passenger-oriented multimodal air journey: 1) integration of booking systems; 2) whole journey guidance; 3) transfer time and ease; 4) baggage management; and 5) disruption management. We found that delivering these PEFs necessitates support processes within and between organizations to align, including IT, infrastructure, scheduling, operations, commercial, interorganizational, and strategic efforts. Additionally, external conditions – such as market dynamics and regulatory frameworks – play a pivotal role in either enabling or constraining these efforts. We discovered that these underlying support processes converge in delivery mechanisms that influence the provision of PEFs for multimodal air travel. The findings emphasize that while airlines often lead in shaping the multimodal experience, progress is hindered by fragmented responsibilities, misaligned incentives among operators, and market competition. It is crucial to recognize that delivering passenger-oriented multimodal journeys requires effective cross-system collaboration, and that a regulatory framework must be established to create conditions for more sustainable transportation integration.

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.

This paper explores the strategic importance of multimodality for airport hubs, especially considering sustainability goals that are pressuring airports to innovate. Although the European Commission (EC) has encouraged the transformation of airport hubs into multimodal transport hubs since 2011, most airport hubs prioritise aviation transfers over true multimodal connectivity. In response, Schiphol Airport has been taking active steps toward a multimodal future, supported by a collaborative PhD project with TU Delft, following an action research approach. Through iterative research cycles, this study reflects on Schiphol Airport’s efforts to address passenger needs and enhance multimodal services. The research includes cases focused on improving passenger experience in multimodal trips, developing a support system for rail/bus transfers, enhancing information services and conducting strategic sessions with key stakeholders. The findings show that creating a seamless multimodal travel experience requires attention to passenger needs for clear navigation, efficient hub facilities and consistent, real-time information throughout the journey. Reliable updates and knowledgeable staff enhance travellers’ confidence, while special transfer services and efficient coordination make the process smoother. Practical challenges persist, however, due to regulatory restrictions and the prioritisation of airline operations over multimodal initiatives. Achieving a robust multimodal system requires coordinated efforts across sectors and regulatory, infrastructural and service improvements. Overall, the findings highlight that long-term success in multimodal travel relies on deep collaboration and a shared vision among operators, hubs and mobility service providers, with the action research approach offering an effective way to facilitate this process by focusing on underlying needs and building trust among stakeholders.

The rise of multimodal travel underscores the need to design a cohesive journey that considers the passenger experience from start to finish. Achieving this requires integrating diverse travel modes and coordinating infrastructure and mobility services, especially at major transport hubs. This research employs qualitative methods to study passengers’ experiences in multimodal travel involving air transport in-depth. Using autoethnographic and interview methods, researchers and practitioners undertook a total of 26 multimodal journeys involving air transport at four European airport hubs to study the travel phases these journeys and factors influencing the experience. The findings indicate that multimodal journeys involving air transport differ significantly from traditional air-to-air journeys. Multimodal passengers encounter friction as they must cross more system boundaries compared to single-mode travel, with each system governed by its own distinct rules and regulations. Consequently, multimodal journeys require different passenger flows, infrastructure, and services than air-to-air journeys. This research identified eight journey integration factors that impact the passenger experience of multimodal journeys involving air transport: (1) journey explanation and preparation, (2) personalized and pro-active assistance, (3) wayfinding, (4) proximity of modalities and facilities, (5) multimodal transfer services, (6) balanced transfer time, (7) waiting environments, and (8) in-travel comfort. Importantly, the passenger experience in multimodal journeys involving air transport is influenced by passengers’ expectations and cannot be understood in isolated segments, as travel phases are interdependent. This highlights the importance of designing multimodal journeys involving air travel as cohesive units and emphasizes the crucial role of collaboration among actors across transport systems.

Future mobility systems will likely incorporate more multimodal journeys. These multimodal journeys integrate multiple modes of transport, and their higher future prevalence highlights the importance of paying attention to the modality transfers within journeys. To carefully facilitate these transfers, we advocate the creation of passenger-oriented Multimodal Transport Hubs (MTHs), which integrate both infrastructure and services of multiple travel modalities to ensure high-quality transfers between the different modes of transport. This study is part of a research project investigating how Airport Hubs can transform into MTHs and aims to learn in practice how the case study FlyHub deals with new travel modalities and how FlyHub integrates these into its ecosystem. Through the presence of an embedded researcher in the case study context, performing the explorative pre-step of the Action Research approach, the study builds an understanding of the context and the rationale for possible succeeding cycles of action and research. Accordingly, we identified five themes that either stimulate or thwart the transition of FlyHub into an MTH. The five themes are 1) recognition of the importance of innovation and long-term outlook, 2) limited exploration possibilities, 3) the MTH concept being (too) abstract, 4) multi-system transition going slow, and 5) changes and transitions being a struggle for power.

This poster presents the “Accelerating Innovation” programme, a set up for
three PhD research projects that was created within the collaboration between the
Royal Schiphol Group and the Industrial Design Engineering faculty of the TU Delft.
With this collaboration, researchers from the IDE faculty were engaged in three challenges: (1) designing towards pandemic antifragility in Multimodal Transport Hubs (MTHs); (2) transforming Airport Hubs into passenger-oriented MTHs, and (3) investigating the adoption of autonomous processes in the context of organizations. An action research methodology is followed in the projects, meaning that the researchers are embedded in the organization, and actively participate in daily
practice. This poster presents the scope of the three projects, as well as the studies and academic supervision tasks that the researchers have undertaken until now; we hope to contribute with an example of action-research oriented PhD projects, which could serve to ilustrate transdisciplinary research perspectives.

Developments in sustainability and digitisation outline a future of mobility, with multimodal transport becoming the new normal. Travel modalities will no longer be the focal point of mobility, but passenger experiences and the services that provide these will. In a mobility landscape where the passenger experience is key, and multi-leg trips are the norm, Multimodal Transport Hubs are essential players as they can facilitate high-quality intermodal transfers. However, this advanced application of Multimodal Transport Hubs does not yet exist in practice. By employing a scoping review, this research aims to investigate the position of airport hubs as Multimodal Transport Hubs in the future of mobility, as airport hubs physically unite several transport infrastructures but only offer transfers with high-quality services within air traffic and not – to, from and between other modalities. To become future-proof, airport hubs should transform into truly Multimodal Transport Hubs that provide transfers with high-quality services from at least ultra-long to long and medium-range modalities. However, airport hubs have features such as a complex stakeholder landscape, long development times, reliance on transport operators and uncertainty about the added value of integrating new travel modalities that make modality innovation at airport hubs a systemic design challenge. This research identified a lack of theoretical knowledge regarding harnessing and integrating alternative and new modalities at airport hubs to transform them into fully integrated Multimodal Transport Hubs. In particular, how to assess and select new and alternative modalities, how to determine the appropriate level of engagement in different stages, and how to integrate new modalities at airport hubs should be investigated in future research.