<p>Agile methods have shaped the development of enterprise software systems during the last two decades. However, many modern cyber-physical systems (CPS) are still developed in as yet waterfall-like processes. The consequence is that CPS development misses out on such advantages of agile methods as handling changing requirements providing fast updates, or dealing with fast feedback on product quality. This is especially problematic today, when the software in CPS systems is more networked than ever, requiring updates to keep pace in an ever evolving network-connected technical environment, as well as patching too often software-induced cyber-security vulnerabilities. In sum, modern CPS must be developed so as to meet the need for updates at intervals of rapidly accelerating frequency. In this paper, we discuss the lack of systematic cross-model consistency management as one of the reasons why established agile methods are not used in CPS development. We present a road map that leads to systematic consistency management, laying the foundations of novel agile methods in CPS development. We discuss solutions in the context of model-driven automotive systems engineering. This domain especially can serve as a litmus test of agility in CPS development, because automotive systems engineering stands to benefit substantially from agile methods to address such pressing issues as strong assurance of dependability and configurability while also offering the flexibility of software over-the-air updates.</p>