Continuity mistake: In the episode "Lost Time," when the professor stands up in the holding cell after Jack tells him that someone saw Skye at 10:30, he slams his chair back causing it to tip over. In the next shot the chair is upright, then when he goes to sit back down, it is again on its side.
Continuity mistake: In episode "One for All," when they are first at the school looking at the seating chart, Danny states that the teacher said that all the students are in their assigned seats. Malia's name is in the first row second seat, but she is actually sitting in the first row first seat.
Continuity mistake: At the end of the show when Jack tells his wife that he wants to go with her and he hugs her; at the beginning of the hug the wife has a champagne bottle in her right hand, but when they release each other from the embrace, Jack is holding the champagne bottle in his hand.