A folding wing comprises a wing root, an upper wing part foldable relative to the wing root, at least one guiding device, and an elastically pre-stressed force element. The upper wing part comprises an end edge and a profile foot, wherein the wing root comprises a base and an opposing receiving groove, which is designed to receive the profile foot in a flush manner and is delimited by two delimiting edges having a separation distance that at least equals the maximum profile thickness of the profile foot. The guiding device is arranged at one of the upper wing part and the wing root and is designed for guiding the profile foot in a variable distance to the ground of the receiving groove. The force element is coupled with the wing root and the upper wing part and urges the upper wing part into the receiving groove through the pre-stress.