Rare official card from the flight of the Postluftschiff Schwaben that pictures the sons of the Grossherzog (Grand Duke) of Hessen in Summerkleidung / summer clothes. Sieger 'G'. Slightly worn at the edges, excellent condition, as per scans. Franked with the 'goose' Michel I semi-official airmail. Flugpost am Rhein u. am Main Darmstadt cancel.