You are probably thinking of the inverted Jenny air-mail stamp --probably the most famous error ever in US stamps.
One sheet of the 24 cent airmail stamp was printed with the airplane printed up-side-down and sold before the error was discovered. This is undoubted the most famous error stamp in US postal history.
The cast of Goodbye 1918 - 1918 includes: Mona Moore as 1919
The issue was that women were not considered "persons" and did not have as many rights as the men did.
RAI= Regular Army issue; 1918=year of make/issue; US339471=serial nr.
The cast of He Got His - 1918 includes: Victor Moore
The cast of Bauernehre - 1918 includes: Georg Burghardt
The cast of Cronstadt - 1918 includes: Max Maxudian
The cast of Why Not Marry - 1918 includes: Jimmy Aubrey
The cast of A szerzetes - 1918 includes: Victor Varconi
The cast of The Decision - 1918 includes: William Duncan
The cast of Haine - 1918 includes: Suzy Prim
The cast of After Henry - 1918 includes: Sidney Drew