Following the United Kingdom’s departure from the European Union and the transition period that followed, the UK and EU have embarked upon a journey to form a new relationship. With the entry into force of the EU–UK Trade and Cooperation Agreement (TCA) in May 2021, now is an opportune moment to consider what has been achieved and what is yet to come in the areas of competition (antitrust rules and merger control) and State aid. This article examines the current state of play in these important areas for ongoing and future international cross-border activity, in which international airlines play a central role. It identifies and reflects on the key ‘moving parts’ in this unchartered EU–UK regulatory environment: law reform, the competition authority’s role and future regulatory cooperation.