This chapter reviews the extant understanding of the fundamental capabilities that humans can contribute to aviation operations. The chapter examines how the pilots adapt to the changing aviation environment as information processing demands shifted from direct perceptual-motor control of the aircraft flight path and attitude to more complex and strategic, higher-level processing enabling the aircraft to safely operate in otherwise untenable regimes (e.g., night flight) and more crowded airspace. How limited human attention is mobilized, allocated, and optimized to meet the myriad challenges of the aviation environment is discussed. The interplay between the essential skills that enable performance and the human biases that can conspire to produce errors is examined. Last, the pragmatic need to characterize the demands of information processing has led to the development of the concepts of mental workload and situation awareness to help guide design and to assess the effectiveness of aviation systems. Considering the extant knowledge of human information processing and emerging technological trends, the chapter looks forward to a likely future aviation system.