Gaffes

The lighting changes between the live and the obvious studio shots of Hale parachuting from the plane in the opening sequence. For example, there are 3 light sources in the studio shot reflected on his helmet (including one from in front of him as he looks out from the plane), rather than just the sunlight from above.

Obvious stunt double in place of Sean Connery in the opening skydiving sequence.

In the shot where the rocket approaches the radio-controlled model airplane (36:50) a wire is visible that shows that the rocket is actually bring towed by the airplane rather than flying under it's own power.

Sean Connery's character frequently uses a CP-16 film camera, which requires a large set of batteries worn around the camera operator's waist. Sean Connery is never wearing a battery belt, and in close ups, the battery connector on the camera is not connected to anything.

Unger's weapons warehouse is in France as evidenced by the French sign behind Sean Connery as he rings the doorbell and the "SORTIE" exit signs. Inside the warehouse, the electrical outlets are Type B (American) rather than the Type C or E that is found in France. The light switches are American style as well.

(at around 1 min) The design of the suitcase bombs is shown to President Lockwood. The bombs are said to contain plutonium, but the design shown fits the uranium bomb (the cannon design), not plutonium bomb (the fission sphere design) - a very distinctive difference President's aides should know.