AIRMAIL, Windhuk National Exhibition. For the exhibition in Windhuk from 29 May to 4 June 1914, Berlin mail-order firm Rudolf Herzog sent a Pfalz biplane with pilot Bruno Büchner to South West Africa. Büchner arrived Swakopmund on 5 May aboard steamer "General" with the biplane still to be assembled; the Pfalz biplane from Speyer aircraft works was transported by steamer "Winfried". After test flights and paid exhibition flights over Swakopmund, he departed 18 May 1914 at 6.30 local time, following the railway via Usakos-Karibib-Okahandja to Windhuk. Mail was also collected at stops in those towns. - The airmail, more than complete: six different stages (3 postal stationery and 3 picture postcards) of Bruno Büchner's German South West Africa flights as listed in the Arbeitsgemeinschaft Sammler Deutscher Kolonialpostwertzeichen catalogue. Including 2nd stage of 19.5.1914 sent to Germany; nearly all other known airmail cards were carried within German South West Africa. Every card with "faultless" certificate from Czimmek BPP, Jäschke-L. BPP, Bothe BPP or Steuer BPP. A complete airmail collection of all six ARGE-listed stages is an exceptional offering, as only three truly complete sets exist worldwide. All six cards in finest faultless condition. A unique opportunity for the advanced collector to add these decisive airmail rarities to a German South West Africa collection; their rarity makes such an offering a once-in-many-years event!