Continuity mistake: When Monty punches that guy at the end, check out how the parting of his hair goes from left to right and back again in one shot as he falls and gets up.
Continuity mistake: When Brewster goes to buy a stamp, the shop owner shows him the upside down airplane stamp. He is holding the stamp with a pair of forceps. The stamp is shown from the back, then from the front, then the back, and the front again. The view from the back has the forceps holding the stamp at the same angle. The views from the front has the stamp being held at two different angles.