Auction #93 Worldwide Air Post stamps and postal history, Zeppelin Flight items, philatelic rarities of the World

1924, National Aviation School, 10c-5b, complete set of seven, positional blocks of six (2x3) 10c, 25c and 50c, three-side margin block of ten (5x2) of 2b with complete inscription on bottom selvage, perforated proof of 10b in brown orange and black and more, full OG, NH or LH/hinged, mostly VF and interesting assemblage, Est. $300-$400