1937年上海寄美国泛美航空首航封2件，首航封样式不同，均贴京三版航空45分1元各一枚，销上海4月26日戳，另盖不同戳式首航纪念戳，均有三藩市5月4日机盖到达戳，保存完好ChinaPostal HistoryRepublic of China1937 (26 Apr.) First flight airmail from Shanghai to U.S.A.in two different style commemorative covers, both bearing air mail issue 4c. and $1 tied by Shanghai c.d.s., showing two different style commemoratve handstamp, both with San Francisco arrival c.d.s. (4.5), fine. (2)
