The ER-2 X-Band Doppler Radar (EXRAD) ALOFT dataset consists of radar reflectivity and Doppler velocity estimates collected by the EXRAD onboard the NASA ER-2 high-altitude research aircraft. These data were gathered during the Airborne Lightning Observatory for Fly’s Eye Geostationary Lightning Mapper Simulator and Terrestrial Gamma-ray Flashes (ALOFT) field campaign. ALOFT aimed to study terrestrial gamma-ray flashes (TGFs) and gamma-ray glows in thunderstorms and to validate observations from the International Space Station Lightning Imaging Sensor (ISS LIS) and the Geostationary Lightning Mapper (GLM). Data files are available from June 15, 2023, through July 31, 2023, in the HDF-5 format.