Hong Kong - specialities: 1931, DO.X flying boat first flight Europe-South Ameri
Hong Kong - specialities
1931, DO.X flying boat first flight Europe-South America-USA with respective boxed red cachet franked 6.25 RM "Friedrichshafen 13.11.29" and dispatch of air boat "Dornier DOX 3 JAN 31" addressed to Bitzer&Co., Hong Kong. Transit "Rio de Janeiro 22 VI 31", there are no more transit or...