Requirements engineering is a creative process in which stakeholders and designers work together to create ideas for new systems that are eventually expressed as requirements. This paper describes RESCUE, a scenario-driven requirements engineering process that includes workshops that integrate creativity techniques with different types of use case and system context modeling. It reports research in which RESCUE creativity workshops were used to discover stakeholder and system requirements for MSP, a future air traffic management system to enable the more effective, longer-term planning of European airspace use. The workshops were successful in that they provided new and important outputs for subsequent requirements processes. The paper describes the workshops structures and results, and answers 3 important research questions.