1911, INCOMING MAIL-GB, ”FIRST U.K. AIRIAL POST”, special event pictorial postcard with green imprint from London to Windsor, showing ”Instructions of the organising commitee”, on backside, bearing two KGV 1/2 d green oblit by special event postmark ”LONDON 3 SP 9 1911” address sed to CALCUTTA/INDIA with arrival cds ”GARDEN REACH DELI CALCUTTA 1 OC 11”. Extremel scarce. First airmail post from GREAT BRITAIN TO INDIA! Only a few exist! RR!