Selection of military pilots has long included the use of multiple aptitude test batteries. Although the names and appearances of the tests used in pilot selection vary, most are to a large extent measures of general cognitive ability, or g. This is consistent with the central role played by cognitive ability measures in the prediction of numerous job training (r = 0.43) and performance (r = 0.34) criteria. Measures of specific cognitive abilities (e.g., verbal, quantitative, spatial, perceptual speed) have shown little incremental validity beyond g (increase in correlation of about 0.02). The incremental validity, beyond g, of measures of pilot job knowledge (e.g., aviation concepts, instruments, principles and terms; increase in correlation beyond g of about 0.08), psychomotor abilities, and personality scores (increase in correlation beyond g between 0.02 and 0.04) also has been small, but significant. The unavoidable requirement to reason in responding to test material causes g to be measured. In broad-ability-range samples, the positive correlations of the measures demonstrate that general cognitive ability is always present as a higher-order factor. Future measures of pilot aptitude may include tests based on cognitive components, chronometric methods, neural conductive velocity, or other methods. These measures, despite their appearance, have been shown to mostly measure g. Subsequently, we expect that future U.S. Air Force pilot selection tests will mostly be measures of g and will, therefore, continue to be predictive of performance.