National insignia on the P-40s in the initial strafing sequence changes from early war (white star on blue circle) to late war (white bars added to sides of blue circle) as the planes land.
When Marty comes running after checking on the burning plane to talk to Lightning, the plane number changes from A3 to A2.
In the closing scene when Sofia is walking with her groceries, the wings she is wearing change from the left to the right side.
When Cuba Gooding Jr. is using a map to explain an upcoming mission he is using his pipe to point to the map. In the next shot the pipe is suddenly in his mouth.
During the review of gun camera footage of the train attack, Major stance lights his pipe with a flourish of his lighter holding the pipe with his left hand. The cut to another camera has him holding the pipe with his right hand and his left in his pocket.
In the opening scene, the German flight leader is not wearing his oxygen mask throughout the entire battle. B-17 missions were routinely at altitudes of 25,000 feet (all the American characters are wearing masks). Without the oxygen mask, the German commander would have passed out in a matter of minutes.
Whenever P-51 Mustangs are shown in flight, they are accompanied by their trademark gun port whistle, even while in level flight. In actuality, the whistle only occurs during high G turns and climbs, when the angle of attack on the gun ports is sufficient to create the sound. Some attribute this noise to the supercharger on the Rolls engine, however in fact it is created by the gun ports, and as such demilitarized P-51s with their gun ports removed do not make the sound.
Fighter escorts for bomber squadrons flew alongside them on the flanks rather than in formation with them.
When the pilots attack the German Navy vessel, it is referred to as a "destroyer". However, the close ups of the attack reveal the vessel has multiple 8-12 inch guns in armored turrets, which would make it at least a cruiser and maybe even a light battleship.
The term "squad" is/was not used the air forces of WWII. A fighter or bomber group is made up of several squadrons. Each squadron is then composed of "flights" or "section".
The air bases in the movie are clearly from the jet era, with their very tall control towers and long, paved runways. Unlike jets, propeller driven planes do not require paved runways, and wartime air bases tended to be simple grass.
Throughout the movie, both fighter planes and bombers are seen bursting into flames and/or exploding mid-air after being hit by only one round. Shooting down a war plane was much more difficult, and they would regularly return to base riddled with bullet holes but intact. In particular the B17 Flying Fortress was an extremely durable plane, and even an Me262 jet fighter usually had to make several direct hits with their high calibre 30mm cannons to down one.
Throughout the movie, the pilots do not seem to experience any effects from G-forces whatsoever, even though at one point, they dive straight down for more speed and pull up to chase the jet fighters.
P-51s of the time were bright silver in appearance due to their unpainted aluminum finish. The P-51s in the film are obviously painted silver. (This is quite understandable, as the aircraft used for filming all came with different finishes and had to be repainted.)
The searchlight in the POW camp appears to have come from the studio's lighting department as the ears for the barn doors are visible.
The movie begins in "1944". It looks like it is summer, maybe May. Soon, it is announced that Operation Shingle is to be launched. That was on 22 January 1944. The weather and leafy trees are wrong for the season.
During the raid on Berlin, the fields look like they've been harvested in late summer. The raid took place on 24 March 1945, and the fields would be ploughed without any growth.
The radio behind Col. Bullard's desk is an RME-45 receiver. Manufactured for the amateur (ham) radio market, it did not t go into production until after WW2 (1946-1947).
Although the film opens with a title that says 1944, the song being played at the U.S. base is "It's Been a Long, Long Time," which was written by Jule Styne and Sammy Cahn to celebrate the war's end and not released until 1945.
When Joe 'Lightning' Little is being reprimanded by Colonel A.J. Bullard in his office, Joe is wearing his headgear. But when he steps out of the office he is no longer wearing it. This is backwards. Army regulations state that when a soldier is outdoors, he is supposed to have his headgear on. He is then supposed to remove his headgear as soon as he steps indoors.
During the initial bombing run to Berlin, one of the bomber pilots says that engine number three is losing pressure, but when the shot goes to the plane's exterior, engine number one has stopped operating.
The German antagonist "Pretty Boy" uses the wrong German term for fighter planes. He calls them "Kämpfer", which would be the literal translation of "fighters". Correct would be "Jäger" or "Jagdflugzeuge", which translates into English "hunter" or "hunting planes".
The plural "Aircrafts" is used where common usage would have been "Aircraft."