Former U.S. Army, 509th Parachute Infantry Regiment Beret Flash and jacket patch of World War II
Background: According to some historians, the first US military use of a beret flash was created and worn by the 509th Parachute Infantry Regiment (PIR) who trained with the British 1st Airborne Division during World War II. The 509th PIR were made honorary members of the British airborne forces, entitling them to wear the maroon beret worn by British paratroopers. Some of the paratroopers from the 509th PIR had a small hand-embroidered version of their regiment's gold and black pocket patch—depicting a stylized figure of a parachutist standing at the exit–door of an aircraft with the word "GERONIMO" blow it—created for use as their beret flash on their honorary berets. This is believed to be the first organizational beret flash in the US military who's heraldry carries on in the 509th PIR's distinctive unit insignia and coat of arms. —See Source section for citations.
Created by English Wikipedia editor User:McChizzle using sources such as:

https://www.worthpoint.com/worthopedia/wwii-509th-parachute-infantry-1817698415;
https://www.509thgeronimo.org/uniforms/uniformberet.html
"Beret Insignia of the U.S. Army," by William A Hudspeath, published by Richard W Smith, Hendersonville, dated 1987, ASIN B06XD7DSY9