An aircraft outer skin heat exchanger includes a first cooling air inlet and a first cooling air duct section, in which a first heat carrier fluid duct section is arranged. A cooling air conveying device is configured to convey a cooling air stream in such a way through the first cooling air inlet and the first cooling air duct section that the cooling air stream is subdivided by a first heat carrier fluid duct section, arranged in the first cooling air duct section, into two partial air streams which flow through the first cooling air duct section substantially parallel to one another and in the same direction.