Yeah, according to the Alien: Quadrilogy box set special features, everything in the movie is designed to trigger one huge Vietnam War flashback ... and considering the movie came out just 11 years after the war ended, it wouldn't have been that far from the audience's mind. First, we have the dropship, which was modeled after U.S. combat aircraft of the era:
20th Century Fox, Staff Sgt. Phil Schmitten/US Army
After mating them with giant crabs.
Then we have the general design of the soldiers: Their weapons, outfits, and even the designs they paint on their gear are based on the ways that American soldiers used to decorate theirs during the war.
20th Century Fox, military.com
20th Century Fox, eastofeton.wordpress.com
"This platoon has a minimum 15 pieces of flair."