During the first bombing run at the beginning of the film, damage is seen on the cockpit canopy, which disappears and then reappears between shots.
Bogart's Co-Pilot Hinkle completed 25 missions and was being sent home. Yet when he post-war meets up with Bogart and takes him a party he tells him a story about being shot down in Europe in 1943. If it had happened while flying with Bogart he would already know the story plus they would not have been sent over Europe again for security reasons.
When Matt is in the pod parachuting down and unloosens his oxygen mask; he still has his headgear on which includes a helmet, headphones, and oxygen mask attached as well as being strapped in. However, when he touches the ground and is groggy from the impact as he exits the podcast; he no longer is wearing the headgear. Additionally, he is not strapped in.
Splatter on outside of Bogie's left window appears, disappears, then is back again while in flight.
When Jo is at the table with the various soldiers there is only one champagne bottle in the bucket and she grabs it. However, on the next cut, the bottle is still in the bucket. Additionally, the orientation and amount of champagne bottles in the bucket and on the table change from shot to shot.
After Brennan starts the JA-3's engine, Bostwick yells 'clear!' This should have been said before starting the engine, to make sure no one is standing near the exhaust.
When the B-17 is landing at Bassingbourn with one gear up, the emergency vehicles rush out to the crash. One of the ambulances has "U.S. Air Force" on the door. There was no USAF until 1947 - the correct marking would have been U.S. Army Air Force.
Both aircraft flown in the movie, JA-3 and JA-4, are supposed to be jet aircraft (hence the JA identifier). However, neither aircraft has air intakes that are necessary for jet engines to operate.
When the B-17 comes in for a landing at the beginning of the flashback the Pilot, Humprey Bogart/Major Matt Brennan, is in the Co-Pilot's seat on the right NOT in the Pilot's seat on the left. There is no good reason for the pilot and co-pilot to switch seats.
The technician/aircraft expert keeps referring to the Me-163 that attacked them in the 1943 mission as a "Jet". the Me-163 was a Rocket Interceptor that only operational from mid-1944 defending the German Homeland.
Matt Brennan makes reference to the German guns on their fighters as 20 "em - em". They were actually called "20 millimeter." "MM" is the abbreviation for "Millimeter" so this is not an error.
Wires visible on JA-3 model. Additionally, the wires suspending the model are going off to the side, revealing that the crew flipped the camera to create the illusion of the plane maneuvering a certain way. Also, when the full-scale plane is used, when taxiing, a cable can be seen pulling it in some scenes.
While flying the JA-3 for first time, Bogart's shoulder harness over his right shoulder is stenciled with "left",
When the JA-4 is moving to taxi, the crew ladder (near side) is removed; however, the A-frame ladder (far side) is not moved, and the JA-4 starts the taxi with that ladder and 2 personnel are going to be taken out by the starboard (right) wing.
In 1943 there were no German jets in action yet. The first operation of the "Messerschmitt Me 262" against US-bombers was in March 1945. The Me 262 had two jet engines attached under the wings, the jets shown in the film have one engine inside the tail. The plane that is being shown in the footage is the Rocket Powered Me-163 that was flying later than the Me-262. Neither of these planes were operational in 1943.
When Troxell first taxis the JA-4, it can be seen that the "4" on the side of the plane was just a decal placed over the "3" on fuselage used for all the ground scenes.
After Matt takes off when he is supposed to be just doing taxiing tests, a gauge shows his airspeed is over 1,100 miles per hour - meaning he broke the sound barrier, but no sonic boom is heard or mentioned by the crew on the ground.
Extra wing rockets on the jet change size and even vanish and reappear before they are eventually dropped off.
The Washington radio controller talking to the Baffin Bay controller is mouthing the words "JA-3" over the "Baffin Bay" audio, as though a script or plot change occurred after filming.
A shortest-distance flight from Nome, Alaska, to Washington, DC, would not go over the North Pole. It would pass over the Yukon and Northwest Territories of Canada, as well as the provinces of Saskatchewan, Manitoba, and Ontario. Furthermore, such a flight would pass a considerable distance from Harrisburg, Pennsylvania. A major plot point in the picture involves the JA-3's flying over the Pole, and Harrisburg is mentioned twice during the flight as being in the path.