This stamp was issued for use on flights at the Marguerite Flower Festival in Leipzig-Lindenthal, 18 May 1912. The stamps exists in two shades of blue.
In 1912, the Hessen Royal Family hosted a “Postcard Week” for the purpose of raising funds for the Grossherzogliche Zentrale fur Mutter- und Sauglingsfursorge, a home for mothers and infants. The charity was originally scheduled to last from 10-16 June 1912, but was later extended to 23 June.
Shown below are the stamps of the GermanStamps.net Collection on the physical album pages.
Unlike official airmail stamps, semi-official airmail stamps were issued by aviation companies, air shows, and other aviation-related organizations. The semi-official airmail stamps paid the fee for transport of the mail on a particular airplane, glider, or balloon flight.