Bidspirit auction | Worldwide Aerophilately - Macao

Worldwide Aerophilately - Macao - 1940, New York World's Fair, green overprint on 50a red brown, two singles, one has inverted overprint, full OG, NH, VF, an undoubted worldwide air post rarity, only 25 stamps were produced with inverted overprint, expertized by S. Wolf , Sc. #C13 fn