Joe is able to board the plane despite being last up the stairs.
On the drive to Washington the guys are shot at by 'agents' in the car behind. Joe returns fire shooting out of his car window left handed... When he finishes shooting them off the road the view changes and he is now holding the gun in his right hand.
In the scene in Glen's bedroom, we see Quagmire has a mirrored ceiling. The abstract art on Glen's wall has a red triangle in it but in the reflection, the triangle is missing
In the scene where the guys arrive at the hotel, they park the car in front of the entry door. When entering the hotel, you can see through the door, that there's no more car standing there.