Abstract: A solar powered hot air balloon is disclosed having an envelope with an opaque portion and a transparent portion arranged so as to utilize solar heating to heat air within the envelope. The solar heating air may either by sufficient to provide the entire free lift or may be combined with air from a hot air generating system carried by a gondola supported by the envelope. The opaque portion of the envelope has a substantially black inner surface and a light reflecting outer surface with the black inner surface being positioned so as to receive a maximum amount of sunlight through the transparent portion for a given average position of the sun.