In the United States, general aviation piston-driven aircraft are now the largest source of lead emitted to the atmosphere. Elevated lead concentrations impair children’s IQ and can lead to lower earnings potentials. This study is the first assessment of the nationwide annual costs of IQ losses from aircraft lead emissions. We develop a general aviation emissions inventory for the continental United States and model its impact on atmospheric concentrations using the community multi-scale air quality model (CMAQ). We use these concentrations to quantify the impacts of annual aviation lead emissions on the U.S. population using two methods: through static estimates of cohort-wide IQ deficits and through dynamic economy-wide effects using a computational general equilibrium model. We also examine the sensitivity of these damage estimates to different background lead concentrations, showing the impact of lead controls and regulations on marginal costs. We find that aircraft-attributable lead contributes to $1.06 billion 2006 USD ($0.01–$11.6) in annual damages from lifetime earnings reductions, and that dynamic economy-wide methods result in damage estimates that are 54% larger. Because the marginal costs of lead are dependent on background concentration, the costs of piston-driven aircraft lead emissions are expected to increase over time as regulations on other emissions sources are tightened.