Deliberate mistake: After the alien ship destroys the bomber, Dr. Marvin picks up the helmet and they all start to run back to the car. In order to save time in repositioning the camera they start out 50 feet behind where they just were in the previous sequence and run back to the exact same spot.
Deliberate mistake: After the aliens announce their intentions Dr. Marvin meets with Carol back at their hotel room. He tells her that she must take a flight alone back to Palm Springs and then leaves the room. In the end of the scene she picks up a copy of The Evening Star, which is an obvious prop as it has no date on it.