A sealing system on a first structural element having a first through-opening, including a first closing flap rotatable about an axis for closing the first through-opening. The sealing system can be coupled to a second structural element. The first closing flap is provided with a first dynamic seal on the radial outer circumference thereof. An elastic seal is provided on the wall of the first through-opening and adjacent the first dynamic seal. The inner diameter of the elastic seal is smaller in the non-operated state than the outer diameter of the first closing flap. The first structural element is provided with a second closing flap which essentially matches the first closing flap and can be swivelled together with the first closing flap. The dynamic seal can be inflated radially towards the outside by means of inner pressure when the first closing flap is in the closing position and in such a way that the elastic seal is at least partially and radially displaced towards the outside.