Using the case of Canada's airport policy, this dissertation seeks to give an account of longlasting conflicts between key actors of a policy sector who otherwise do not challenge the core policies and orientations of their sector and share the same core representations. The argument of this dissertation offers a response to the paradoxical outcome where a long-lasting policy has remained stable over time, despite engendering momentous conflicts and tensions between actors (to the point of threatening the stability of the policy sector) and being attacked by virtually all actors. This objective is sought by analyzing the Canadian airport sector and its four main platforms: Toronto, Montreal, Vancouver and Calgary. The Canadian airport sector is highly puzzling, since long-lasting conflicts over the airport rent, the access to airport infrastructure and the funding and administration of airport screening have polluted the relations between the key stakeholders for years, while none of the key actors involved has challenged the main policy orientations and policy instruments used to regulate the sector. The study of the Canadian airport sector with a refocused and amended cognitive analysis of public policy framework developed by Muller and Jobert is really fruitful: it results in a comprehensive analysis of the conflicts, their nature, the possible ways to solve them, and it also considerably expands the explanatory power of the cognitive analysis of public policy. iv ACKNOWLEDGEMENTS I would like to thank my PhD supervisor, Dr. Patrik Marier, for his continuous support, availability and guidance during the successive stages of the PhD programme. Your supervision has been a critical success factor in my journey at Concordia, and I appreciate that you accepted to oversee my PhD studies. My sincere thanks also go to Dr.