Obviously male stunt driver during the motorcycle scenes.
During the chase scene of Casey on the motorcycle, a few groups of spectators can be seen on different street corners watching the filming.
When Jim is following Hugo & Phalen to the warehouse, you can see that outside of their vehicle it is raining, there are rain drops on the windows, however, in the very next shot of Jim following them, it is bright and sunny outside.
The air medal on the wall of the air charter service office had the name John R Brady crudely printed with a felt pen rather than being neatly printed.
When Casey removes the device from the motorcycle's spark plug, the engine would have been too hot to do so with bare hands.
When Sam Hibbing (Claude Akins) pulls away from his house to try to intercept Jim Phelps (Peter Graves), first a large studio light and then the film crew is reflected in the driver's side of his car.
As the MI team's police officer approaches Casey's accident, a real SFPD officer can be seen in the background directing traffic away from the filming.
The girl is headed to Sausalito from San Francisco and is shown heading north on the northwestern tip of the San Francisco peninsula, at the entrance to the bay, and west of the Golden Gate bridge. This is a dead end. The only way to travel to Sausalito would be over the Golden Gate bridge.