The plane carrying Casey-as-Kathleen appears to be a Boeing 707 (two turbojet engines under each wing, conventional empennage) as it is landing, but becomes a Boeing 727 (one turbojet engine on either side of the rear fuselage, and a third S-ducted turbojet engine at the base of the T-tail) as it taxis.
When they are substituting the dummy for Lisa's body in the mortuary one man picks the dummy up off the stretcher and puts it on the table. It is stiff and obviously fairly light since he moves it easily. When they are putting the dummy in the coffin it takes two of them and the body sags like a real human body.
About 3 minutes in when the plane is making its landing it is a TWA plane but it becomes PSA when approaching the terminal.
They are supposed to be at the airport at 6:45pm, but the shadows are very short indicating it is close to noon.
Also in the mortuary scene when willy and the guest agent move Casey onto the stretcher to eventually carry her out, the actress appears to help them as she kind of moves around to get on there and then lifts head up and back down once on there.