Vintage MILITARY FLIGHT JUMP SUIT COVERALLS Vietnam/Korea? Full Double Zip sz S

Description

Here is a very interesting jump suit I know nothing about.  It does have a label inside: "Pope Valley, CA 94567".  It is size small and has the previous owner's "SGT Nick Nichols" on the right chest.  It is made of black denim type material.  Zippers work great.  It does have a hole at the crotch and the leg stirrups are fraying.  It appears to be quite small in size:
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Please refer to these measurements instead of going by the stated size, as returns are costly for everyone.  Thank you!
Back length from nape of neck to elastic waist:            17 in.
Shoulder seam to shoulder seam:    17 in.
Armpit to armpit:                  20 in.
Armpit to end of sleeve cuff:        19 in.
Waist: 28-33".  Inseam: 27" not including the stirrups.
Conversion from inches to centimeters: 1 in. = 2.54 cm.
Clothing has been measured flat, UN-pulled.
Keep in mind, there "may be" some give to fabric.
If in doubt,  please feel free to ask questions.