The aviation industry is at a critical crossroad, facing increasing pressure to reduce its environmental impact while managing rising operational costs. As a significant contributor to global CO2 emissions, the sector must find innovative solutions to balance sustainability with economic challenges. However, strict regulations, high material costs, and fragmented supply chains complicate efforts to drive change. This project explores how the Circular Cabin model—a framework for recycling and reusing cabin interior parts to reduce waste and extend material lifecycles—could be integrated into KLM Royal Dutch Airlines' Maintenance, Repair, and Overhaul (MRO) operations.

Cabin interior parts, particularly seats, were identified as high-potential areas for circularity due to their frequent replacement and material composition. A pilot study on seat backrests demonstrated that recycled polycarbonate can meet stringent aviation fire safety certification, representing a major milestone in advancing circular cabin practices. This breakthrough paves the way for further testing and offers a practical approach to scaling recycling practices within aviation.

To translate these findings into actionable steps, a playbook was developed to guide KLM E&M employees in embedding circularity into their operations. The playbook includes tools such as a decision tree for assessing recycling potential, a strategic roadmap for implementation, and focus areas for further research. By connecting strategic vision with practical application, the playbook provides a clear pathway for operationalizing circularity within KLM Engineering & Maintenace’s (E&M) operation.

This project highlights the transformative potential of circularity in aviation. By adopting circular practices, KLM E&M can reduce material costs, enhance supply chain resilience, and create a more level playing field with Original Equipment Manufacturers (OEMs). With a commitment to the tools and insights developed in this project, KLM E&M has the opportunity to become a frontrunner in sustainable innovation, setting a powerful precedent for the industry and redefining the role of aviation in shaping a sustainable future.

Micro, Small, and Medium-sized Enterprises (MSMEs) are essential for every economy due to their impact on economic development, especially for emerging countries. It is crucial to provide them with support in developing and implementing strategies that promote their growth, thereby enhancing the broader economy. This thesis project utilized a medium-sized enterprise as a case study to investigate MSMEs in the Philippines. The primary objective was to align its operations with its strategy of offering a wide range of low-priced products while providing personalized customer service. The project used the Double Diamond by the British Design Council as a framework to approach the project, employing different design methods and tools. The findings revealed the pressing issues are low stock availability, lack of customer-centric experience, and efficient operational processes. From this, the design challenge was centered on redesigning the order fulfillment process service blueprint of the messaging application channel for retail transactions. The design strategies implemented include enabling technologies, addressing stock outs early in the process, and optimizing roles. Efficient Consumer Response (ECR) was utilized as a guide to formulate these strategies for the intervention. The proposed service blueprint received positive and desirable feedback when validated with the employees. As a conclusion, the project's relevance, limitations, and recommendations were described.

Sustainability's role in the current business environment is increasing for several reasons, such as regulatory requirements and consumers favouring eco-friendly practices. Nevertheless, sustainability-focused startups often struggle to scale their impact due to several challenges, including the lack of a comprehensive framework that helps them transform their Sustainable Business Model to be scalable and resilient. This study seeks to connect this gap by creating a framework that aids startups in scaling their operations and impacts using strategic design. The research methodology is structured around the Double Diamond Design Process, starting with an extensive literature review focusing on sustainable business model innovation and scalability, several frameworks that enable them, and some strategic design tools. This is followed by empirical studies involving semi-structured interviews with founders of sustainable startups and a business case workshop, where students are asked to create scale-up strategies for an imaginary startup through a pre-framework developed in the previous phases.
This results in the development of the Sustainability Scale-Up Framework (SSF), which enables sustainable startups to develop resilient scale-up strategies using strategic design. The SSF consists of several interconnected components: Vision, which involves establishing a clear and compelling vision aligned with the startup's sustainability goals and worldview; Value Propositions, which focus on developing innovative products and services that meet stakeholder needs; Value Creation Mechanisms, aimed at optimising processes and operations to enhance efficiency; and Impacts & Strategies, which create implementable strategies to maximise impact. This multifaceted approach ensures that startups can navigate the scaling process effectively while maintaining their commitment to sustainable vision. The study also identifies some common challenges to scaling, like vision alignment and sustainability value tensions, and underscores the role of strategic design in overcoming these challenges by fostering innovation and adaptability. By integrating strategic design thinking with business strategy, the SSF provides a structured and iterative approach to addressing the complexities of scaling sustainable startups.
In conclusion, the SSF offers significant theoretical and practical contributions to the field of Sustainable Business Model Innovation and Business Scalability. It provides a structured approach for startups to scale their impact sustainably, addressing critical barriers and leveraging innovative strategies. Future research could explore the long-term implementation of the framework across various industries and geographies, further refining its components and validating its efficacy. This thesis presents a robust framework that integrates strategic design principles to support the scalability of sustainable startups, paving the way for these businesses to achieve long-term success and impact.

Designers engage with sustainability in their professional practices in a variety of ways. They resort to Design for Sustainability (DfS) approaches, even though they tend to rely on intuition rather than theoretical works. They possess the ability to lead users to individual behaviour change through interventions. They have certain methods and capabilities to transform sustainability challenges into actionable and potentially sustainable futures, and certain shortcomings in skills and education as well as the challenges they face such as workplace conditions and policies which results in them prioritising other factors over sustainability. Given that, there exists a gap in the literature where the point of view on sustainability of professional designers is not adequately taken into account. Through a series of interviews based on a conceptual framework, this thesis aims to qualitatively study and understand the subjective perspective of professional designers on how they conceptualise and assess sustainability in order to detect opportunities to develop new and improved tools, methods, and approaches. Based on the interviews, designers are found to be not the decision makers around sustainability issues and they need to speak the business language to contribute to decision making. They could furthermore advocate by asking the right questions to the right people at the right time. Having said that, it is important to highlight that not everyone is passionate for sustainability and designers may be alone in their battle. Their challenge is to design solutions where user-centricity comes first and are still profitable for them to be effective. One skill of designers is that they could bring awareness via tangible ways, which is especially important for an issue as abstract as sustainability. Implications for designers is that they could look at examples for inspiration, but need to go beyond and nudging the customer is not enough, the product needs to have inherent sustainable qualities. Ultimately, sustainability is a complex, systemic issue yet design interventions are not yet holistic or integral. Through a co-creation session, the problem statement was defined based on the findings from the literature review and interviews. Stemming from a deeper need for guidance and direction, designers need inspiration to imagine new paths of navigating sustainability issues. They face challenges with advocacy for sustainability and the fight against green- washing in their organisations. They need ways of justifying their actions to managers by proving their actions with credible references and need to align and empower stakeholders with different backgrounds on sustainability issues by engaging them through compelling and accessible ways and effectively communicating with them through a common language. In response to this statement, the design intervention Tactical Sustainability Cards was developed. This tool helps the designer at hand by giving them tactics when trying to balance innovation and sustainability in the design process. They furthermore show examples from the industry to benchmark and get inspired. Additionally, they provide relevant academic sources for designers to strengthen their design work. These cards were validated through interview participant feedback and a validation session, and a final iteration is presented.

Achieving a sustainable future necessitates a fundamental transition in both consumption and production patterns, as outlined in Sustainable Development Goal (SDG) 12. The urgency to adapt consumption patterns has grown due to criticisms surrounding the limitations of traditional approaches aimed at decoupling economic growth from energy use. In response, the concept of “sufficiency,” which emphasizes reducing raw material and energy consumption while maintaining quality of life, has emerged as a pivotal component in sustainability discussions.
Within the tourism mobility sector, sufficiency holds particular promise for sustainability, as it encourages behaviors such as shorter travel distances and increased reliance on public transportation. This is especially crucial given that the transport industry significantly contributes to greenhouse gas emissions, with tourism mobility representing a key area for improvement.
This thesis investigates sufficiency and sufficient behaviors within tourism mobility, ultimately leading to the development of a design toolkit aimed at facilitating future projects. The research identifies three types of sufficient tourism mobility—absolute reductions, modal shifts, and sharing practices—alongside associated specific behaviors. A conceptual model integrating the Theory of Planned Behavior (TPB), Norm Activation Model (NAM), and external costs was created to predict these behaviors. Analysis of 191 responses through Partial Least Squares Structural Equation Modeling (PLS-SEM) revealed that subjective norms and attitudes are significant drivers of sufficient tourism mobility behaviors.
To translate these insights into actionable outcomes, a toolkit was developed through iterative design processes, supported by a co-creation session to identify intervention strategies. This toolkit provides resources for designers and stakeholders to foster sufficient tourism mobility behaviors effectively. While the findings primarily reflect European contexts, they offer a foundation for further exploration of sufficiency in tourism mobility design and may inform similar initiatives in other mobility domains.