Hi rk3006.......welcome to TFF.
Can you possibly post a closeup picture of the ring?
The term "Aero Squadron" would place it in WWI. In WWII they were called "Fighter Squadrons".
If, indeed, this is from WWI, then it isn't a "ruptured duck" (honorable discharge). They weren't issued until after May 1943 for honorable service after 9 September 1939.
"In a directive dated 13 May 1944, the War Department General Staff authorized the Honorable Service Lapel Button to be manufactured in gold color metal or gold plated plastic."