1911 FIRST OFFICIAL U.K. AERIAL POST/LONDON POST CARD IN OLIVE-GREEN TO AUSTRIA. Good to fine London post card in olive-green addressed to Vienna, Austria with KGV ½d Downey x 2 cancelled fine strike FIRST UNITED KINGDOM/AERIAL POST LONDON date stamp SP 11 1911 die 3. Scarce overseas usage with note "This is another variety of the Aerial p.c. I understand that they are printed in two colours only, green and brown". (Ref 104395).