In the scene where Richard meets Tommy at the airport, you will notice a very conspicuous inconsistency in the scene (it's the one where Tommy is waiting for his "luggage," which is really a trash sack taped up).

Look to Richard when Tommy drones off with "2, 4, niner..." Every time the camera switches from Tommy's face to Richard's, you'll notice that the airport luggage carts in the back are either there or not there. They appear and disappear depending on when the camera moves back to Richard!