Quantitative studies of the human EEG during signal detection, flight simulation and actual flight performance tasks are reviewed here from the perspective of basic animal research on the neurophysiological and functional correlates of relevant rhythmic patterns. Evidence is examined which relates distinct EEG frequency changes to psychomotor behavior, signal processing and intrinsic attentional modulation during complex performance. Findings indicate that the EEG can provide a valid and objective index for mental effort but, in addition, may reveal task-related cognitive resource allocation, task mastery and task overload.