Zeppelin mail was mail carried on zeppelins, the German airships that saw civilian use from 1908 to 1939. Almost every zeppelin flight carried mail, sometimes in large quantities; the covers usually received special postmarks, and a number of nations issued postage stamps specifically intended for use on mail carried by the zeppelins.
The first zeppelin to carry mail was LZ 4, in July 1908, followed shortly by LZ 3. The early flights did not use any special markings; the first was an oval reading "LUFTSCHIFF / SIGNALPOST" around the edge and "Z III" in the center, used on LZ 6 (Z 3) from August to October 1909. By 1911 a number of different postmarks were in use; a typical example was a circle reading "AN BORD DES / ZEPPELIN / LUFTSCHIFFES", with a date in the center and the name of the zeppelin at bottom. These were actually applied on board the zeppelin while in flight, at a small postal station.
The zeppelins were taken into military service in 1914, and thereafter did not carry civilian mail, although military commanders had special handstamps applied to their mail.
In late 1919, LZ 120 Bodensee resumed flights and mail carriage, using postmarks much as before the war, until 1921 when it was given to Italy as a war reparation. LZ 126 carried mail briefly in 1924 before it was delivered to the United States and renamed the Los Angeles (ZR-3). The Los Angeles carried mail between Lakehurst, New Jersey, Bermuda, and Mayagüez, Puerto Rico several times.
LZ 127 Graf Zeppelin had a long and celebrated career. Within weeks of its first flight in September 1928, the Graf Zeppelin carried the first airmail to go directly from Germany to the US and vice versa. Germany issued special 2-mark and 4-mark stamps for the occasion. On the return trip, the zeppelin carried almost 52,000 postcards and 50,000 letters. In 1929, Graf Zeppelin circled the globe, with stops in Tokyo and Los Angeles. By the time it was taken out of service in June 1937, the zeppelin had made 590 flights, each flight carrying up to 12 tons of mail to and from dozens of countries around the world.