When Jenkins is shot, the windows are closed. We do not hear the sound of breaking glass, but when Hammond gets to his body, the window is wide open.
When McVane flies out to look for the missing airplane, a close shot of the pilot shows his biplane marked "AEZC" (at 23:50). Seconds later, his plane dives, and its marking is "ABTB" (23:56). The lost aviators he's looking for see his plane, and they note the marking is "ABTD," indicating McVane's biplane (24:07). When McVane returns from his search, he taxis up in a plane marked "AEZC" again (24:57).
When Tony mans the machine gun, he sprays the enemy crew with gunfire. Some of the crew are right in front of the plane, so the plane should be riddled with bullet holes, but no bullet holes can be seen.
When Major Hammond goes to Sonia's dressing room, a shadow of the camera can be seen as it tracks down the line of other actresses sitting at their dressing tables.
As Major Hammond is brought by the police into the Air Ministry, the police are greeted by his assistant with "good morning." Moments later the two of them are in Hammond's office and he asks him the time and the assistant replies "a little after four."