The G-1 Flight Jacket was issued to the US Navy, Marines and Coast Guard, and has been in service since the late 1930's. The original G-1 design features bi-swing back and underarm gussets for greater mobility, and single entry button down flap pockets.
Made famous by the AVG in China and Hellcat pilots over the Pacific during WWII! The G-1 is the USN and USMC leather flight jacket, worn with pride by the Phantom crews during Vietnam and the current Tomcat and Hornet pilots. The G-1 is also worn by members of the US Coast Guard.
More technically, the jacket may be considered the U.S. Military flight jacket developed in 1947 and used in the Korean War since the term "G-1" was not used as a label for this fur-collared military-issued jacket until after World War II. However, the term "G-1" has come to be used for this style of naval leather flight jacket. Technically, prior to the end of World War II, and starting in 1940 when it was officially named by the Navy, the jacket had the military spec number of M-422.
This jacket was brought to use by the U.S. Navy in the 1930s, and standardized by the Navy in 1940 as the M-422A. In 1943 this jacket, also named by the Army Air Corps and Navy as the ANJ-3 (Army Navy Jacket 3) replaced the iconic A-2 jacket, the most famous of U.S. Military jackets, hence the name of ANJ-3 (vs. A-2). The M-422A replacement of the loved and famous A-2 was, however, in the form of a non-fur-collared version of the "G-1", currently referred to for obvious reasons as the G-2.