Airborne electromagnetic methods have been applied extensively over the last four decades to exploration for base and precious metals, salinity studies, and geologic mapping. They are becoming more favored as rapid reconnaissance methods to cover large tracts of land, particularly in areas of soil cover. Moving source AEM systems have improved much over the last decade such that lower frequencies and more precise measurements can be made thereby increasing their effective depth of investigation. Further improvements hinge on innovations in data collection and processing.