Motors and generators with power densities in the 30-40 kW/kg are of great interest for electric aircraft propulsion, including both fixed wing and VTOL systems. Such advancements are important for energy sustainability. Rotating machines based on ambient Cu conductors can reach 10-20 kW/kg, but to push further, novel, lightweight conductors are of interest. Here we describe the properties so far achieved with CNT composite conductors both metallized CNT yarn and polymer yarn composites. The electrical and mechanical properties are presented for these composites. For the metallized yarns, tensile tests showed UTS up to 700 MPa, a Young’s modulus of 22.8 GPa , and a specific tensile strength as high as 146 kN*m/kg. Losses were estimated for these conductors based on a new model for composite CNT conductors. Losses due to external field and ohmic contributions were included, and compared to Cu conductors at ambient.