NiCD is reportedly able to release more electrical energy more quickly, than the Nimh. This would result as follows
NiCD would be used to highly power an electric flyer for aerobatics, needing all the power possible NOW, but
NiMH would release it over a longer period of time, as an electric flyer would want to power up to an altitude, then glide, then power up, then glide, or just fly around in lazy eights, or ovals, or touch and gos.