In this paper, we draw attention to the so far largely ignored roles of cost saving software in transport and mobility systems. Based on an in-depth qualitative study of modern flying, we examine the ways in which cost-saving algorithms are increasingly used to bypass human operators and to make complex technological architectures work more efficiently. The case will study the implications of this ‘invisibilization’ of cost management by two types of cost management algorithms that are nowadays an integral part of airplanes’ autopilot: the cost index (CI) and take-off performance calculation (TOP). The study highlights how airlines, over time, have shifted from encouraging pilots to perform manual cost management towards letting the aircraft ‘think’ itself about what makes the flight most cost-efficient. We outline how this shift from explicitly fostering pilots’ cost sensibility towards implanting a cost-saving rationale into an airplane’s technological ‘brain’ fundamentally redefines the ways in which pilots see themselves, how they handle their instruments, what excites them about flying, and how they cope with non-routine situations. We show the unique ways in which such cost-saving algorithms in transport systems infuse us with cost-saving rationales.