Cover franked with pair 1921 4d black & red on yellow GV issue (SG 101) tied by undated AIR MAIL CASTRIES ST. LUCIA cancel with CASTRIES cds alongside dated 25 SEP 1929. Flown on the Castries - Charlotte Amalie first flight to the America Virgin Islands. Addressed to ST. THOMAS with arrival cds on reverse dated 26 SEP 1929. Scarce. (Muller #5, only 194 covers were carried)