Luxembourg: 1936, 1. North America flight, handing in for transport Frankfurt with confirmation stamp \"c\", registered letter from LUXEMBOURG 29.4. With pair 1 3 / 4 Fr airmail and D. Reich 50 Pfg and 75 Pfg Zeppelin with postmark FRANKFURT 2.5. To the United States, 50 Pfg value round corner and slightly spotted, otherwise superb