Other mistake: In the opening scene on the airplane, one of the men tells Lt. Cable, "The captain wants to know if you'd like to sit up in the cockpit with him?" Buzz Adams, the "captain" referenced in this line, is only a lieutenant. Admittedly, "captain" is a standard aviation term for the pilot of an aircraft, but it would be unlikely to be used in this situation, since the term has a specific military meaning.
Other mistake: Both sides (American & German) use the same tanks! The American tanks have white stars painted on them, while the German tanks bear white Maltese Crosses.
Other mistake: In the opening scene, as Captain Glenn Ford is watching a Japanese freighter travel right to left through his submarine's periscope, the freighter is actually going backwards. The bow of the ship is on the right, not the left, as it should be.
Other mistake: During training, when the men are running and the two British men come out of the bushes then shoot at the ground, there are 3 rows of bullets going past but only 2 guns being fired.
Other mistake: In his office Captain Potts unrolls and pins on the wall a Training Progress Chart under the words "Intake No. 29" When the adjutant is calling out of the prize winning platoon at the end of the movie he calls first Prize for the "60th Intake." (00:37:00 - 01:00:17)
Other mistake: In opening scene in the China mission society building, there is a picture of Eric Liddel hanging on the wall. Eric hadn't been born yet.