Factual error: Doug Masters and his friend Reggie would be grounded on the spot and have their pilot's licences suspended (and in all likelihood cancelled) after buzzing the motorcyclist. Their flying is grossly unsafe. They would be visible for miles flying well below a safe altitude, but even if they were not seen their radio traffic and radar tracking would tell the authorities everything they needed to know.
Continuity mistake: In the scene where Bunny kills the one legged Vietnamese with the butt of his gun, watch the cigarette in Sgt. O'Neill's mouth. In a shot after the kid is dead, the cigarette in O'Neill's mouth is short. When it shows him again, the cigarette has mysteriously grown. (00:50:00)
Factual error: At the very beginning of the film, Gunny Highway learns that he's being reassigned to the 2nd Marine Division. The 2nd Division, located at Camp Lejeune, North Carolina, is situated on the NC coast; there are no mountains in the immediate vicinity. However, when the Gunny trains his platoon, he does so in the hills of another Marine training camp located in California. There is a big difference between California and North Carolina.
Continuity mistake: The film is supposed to take place in 1917, but several of the german soldiers our heroes encounter are armed with Bergman M18 sub-machineguns which didn't appear until a year later. To make things even worse all the guns comes with a magazine-type that didn't appear until the mid-thirties.