The whole trope really just comes from the scene in Forrest Gump when Forrest and Bubba arrive in the country by helicopter, which is one of the only times it has actually been in a Vietnam War movie.

Forrest Gump is a simple man with a low I.Q. but good ... Forrest joins the army for service in Vietnam, finding new friends called Dan and Bubba, he wins medals, creates a famous shrimp fishing ...

Forrest Gump is a simple man with a low I.Q. but good ... Forrest joins the army for service in Vietnam, finding new friends called Dan and Bubba, he wins medals, creates a famous shrimp fishing ...