Steponas Darius (born Steponas Darašius; January 8, 1896 in Rubiškė, now Klaipėda district of Lithuania - July 17, 1933 near Soldin, Germany) was a Lithuanian-American pilot. Born in Rubiškė, in the Kovno Governorate of the Russian Empire, Darašius emigrated to the USA with his family in 1907. In 1917 he joined the United States Army, after the United States entered World War I, and changed his name to Darius. Wikipedia
The patch is distinctly engraved as part of the cap of pilot Steponas Darius (1896-1933) who is shown on the face of the note along with his partner, Stasys Girenas (1893-1933). www.michigancoinclub.org/palwaukee.html
The definitive Wikipedia entry for Steponas Darius. Wikipedia is the biggest multilingual free-content encyclopedia on the Internet. en.wikipedia.org/wiki/Steponas_Darius