Character mistake: When trying to teach Banshee to fly, he is told to make his sound waves super sonic. Sound waves cannot be super sonic. Sound can only travel at the speed of sound, it always does. I guess they were trying to tell him to use a very high frequency, but the speed would still be the speed of sound.
X-Men: First Class (2011)
1 character mistake
Directed by: Matthew Vaughn
Starring: Kevin Bacon, James McAvoy, Jennifer Lawrence, Michael Fassbender, Nicholas Hoult, January Jones
Continuity mistake: When Mystique is on the exercise table and Erik lifts the bar off her, her right leg changes from stretched out to bent from the different camera shots.
Erik Lehnsherr: I've been at the mercy of men just following orders. Never again.
More trivia for X-Men: First Class
Question: Charles Xavier knew about Erik Lehnsherr's past, but did he know about those three people he killed at the bar?
Chosen answer: Xavier can read minds, so it's assumed he knows about the murders.