It is really weird to see an airplane in a historical movie like Troy, isn’t it? Was it really a mistake from director’s side or did the actor just time traveled back to the future within a second? Directors and other crew members often do mistakes in movies, since movie making isn’t a 2 hour process as we see them.
In these long movie making period, they take a single scene multiple times. Sometimes even two consecutive scenes actually might have days of difference, although it is not felt the same way when we watch them. And thus Mistakes in Hollywood movies often occurs.
In many films, although spotting out mistakes are real simple, but it is really hard to spot out even a little mistakes from famous movies. You will be even shocked to see mistakes from the movies you watched over dozen times.