Characters in different branches of the service act like they're in the Army.
Sometimes in fiction, when you have characters in certain other branches of the service, such as the Air Force, or even the Marines, based on their conversations and dialogue, you would think that they think they are in the Army. It could be because when audiences see military personnel on the screen, Army is the first thing that comes to their minds; or, it could be the writers simply not getting their facts straight. Either way, it's a noticeable fluke.
ExamplesLive Action TV