When the two briefcases are side by side at the airport, the close up shows the handle of the outer one in a down position but the far shot shows the handles of both in the up position.
When Larry puts the files in his office cabinet, he shows Darrin the key and uses it to lock the cabinet. There is a lock sound, but the keyhole is still facing the same direction meaning the actor never put the key in the keyhole.
When Darrin and Samantha taking a helicopter ride to the airport, the set they are on is obviously an airplane aisle seat, even though the stock footage is that of a flying helicopter .