Commentary Inf XXXIV 46-51

The six wings of Satan are his six wings as one of the angelic order of Seraphim (Isaiah 6:2); they are now not glorious in color but the wings of a giant bat. Their resemblance to sails on a great ship is parodic, since Satan proceeds nowhere, but connects with images associated with Ulysses (Inf. XXVI) and the ship bringing the saved souls to the shore of purgatory (Purg. I).