A flow body for an aircraft includes a torsion box with spars and/or ribs and at least two skin portions for enveloping the spars and/or ribs, wherein at least one inner cell is formed in the torsion box. It is provided that a gas tank with a gas tank shell is arranged in the at least one inner cell, and that the gas tank includes fastening elements coupled to retaining elements in the relevant inner cell in order to hold the gas tank such that the gas tank shell is supported at a distance from the spars and/or ribs and the skin portions and is supported in three spatial directions.