Factual errors: German single-seat fighter aircraft in WWI did not carry externally mounted bombs.
Crew or equipment visible: In two scenes of airplanes crashing (Stachel's first victory, and Willi) the wires suspending the aircraft mock-ups are clearly visible.
Continuity: Stachel's aircraft changes from a Pfalz to a Tiger Moth after he makes his first kill.
Anachronisms: Several British Tiger Moth training aircraft of 1930's vintage were used to represent German fighters. In addition, the "new monoplane" in which Stachel is killed was actually a French Morane Saulnier 230 trainer, also dating from the 1930's.
Anachronisms: The Iron Cross national insignia on the German aircraft were incorrect for that period of World War One.
Revealing mistakes: The German artillery pieces being towed by horses bounce and vibrate too lightly, indicating that they are probably wooden mockups.
Revealing mistakes: In several scenes of burning aircraft, smoke can be clearly seen coming from charges mounted under the wings, rather than from the engine.
Factual errors: Fokker Dr.I triplanes never carried overall lozenge pattern camouflage.
Factual errors: The German award called the "Pour le Merite" (a.k.a. the Blue Max) was awarded at the beginning of the war to pilots who shot down 8 enemy aircraft; that was later raised to 16. The requirement was never officially 20 as depicted here.
Factual errors: The German Army is shown advancing in linear human waves against the British lines in the Ludendorff Offensive of 1918. In fact were really using new storm/infiltration tactics of small well trained and armed troopers. This is where the term "storm trooper" comes from.
Factual errors: The German soldiers were using the British SMLE (Short Magazine Lee Enfield) throughout the movie. The correct German rifle should be the Mauser. Mauser rifles do not have a visible magazine, whereas the Enfield does.
Anachronisms: When the pilots are riding the truck to their lodgings when Stachel has arrived to the squadron, TV antennas can be seen of the roofs of the houses in the town.
Plot holes: Early on, Stachel is seen reading a magazine / newspaper about the "Red Baron" and confesses his admiration and respect. The magazine / newspaper contains a large photo of the pilot on the cover. Later, when Stachel unknowingly saves the Baron's life in a dogfight, he fails to recognize the obvious characteristics of the Baron's plane. Later still, Stachel seems surprised when introduced to the Baron on the ground, as if he doesn't recognize the man's face, although as a fan he'd have seen face on the cover of the book many times.
Continuity: The squadron was issued two triplanes. Willie crashes one. Then in the following attack, a second triplane can be seen behind Stachel's triplane.
Revealing mistakes: When Stachel scores his first victory, the British biplane is seen crashing towards the ground at a shallow angle. But at the moment of impact, it goes from being an entire biplane in this shallow angle to simply a partial fuselage falling vertically straight down to the ground.
Continuity: Stachel's final air battle was flown in the Fokker Triplane. However in the very final shot of him firing his machine guns - he is suddenly shown seated in his (since destroyed) Pfalz scout-fighter - which has a narrower, more rounded fuselage.
Revealing mistakes: During the Ludendorff Offensive scenes, when the German soldiers meet up with the Allied soldiers coming out of their trenches, the bayonets sway back and forth as thought they are made of rubber or foam.
Factual errors: The squadron in the movie that Stachel and von Klugermann belonged to and that Heidemann commanded was referred to as "Jasta 11". Later in the movie, after Stachel saves Manfred von Richthofen's life, Richthofen invites him to transfer to his Flying Circus. In real life, Jasta 11 WAS Richthofen's Flying Circus! in the book it was Jasta 77. But that unit was Bavarian designated in 1918. Thus Jasta 77b.
Factual errors: No fighter aircraft of any nation ever fired machine guns by having the pilot reach up and pull a large lever. The guns were triggered by levers mounted on the control stick which pulled wire cables up to the guns.
Anachronisms: Immediately following Stachel's Blue Max award ceremony the band strikes up the Deutschlandlied (Deutschland Deutschland Uber Alles). This song was not the national anthem of Imperial Germany. In fact, the German Empire never had an official national anthem, although "Watch On The Rhine" (ironically heard a few moments later in the film) was sometimes used as an unofficial anthem. Deutschlandlied did not become the national anthem until 1922, during the Weimar Republic.
Revealing mistakes: In one scene Willi rides in the back of a military truck on his way to pick up Stachel. Exterior shots of the truck show it bouncing very heavily as it drives. This severe up-and-down motion would have made enjoying a bottle of 1903 vintage champagne (or any bubbly drink) impossible.
Factual errors: George Peppard joins the German Flying Service from the ranks of the Infantry. He is shown wearing a visor cap and Uhlan double breasted tunic of the calvary.
Factual errors: In "the Blue Max" Stachel and the other pilots are seen wearing the uniform tunics of the 1st Uhlan Lancer regiment, uniforms modeled no doubt after Manfred Von Richthofen's, as he had a lancer officer before becoming a pilot. However, there never was a "standard" uniform for the German Luftstreitskraefte during WW1. It was made up of volunteers from all branches, and they wore the uniforms they were issued at the time they entered the service. Stachel, although he had been promoted to Lieutenant when he became a pilot, should have been wearing an infantry officer's uniform, not a cavalryman's. Also, there should have been more diversity among the uniforms worn by pilots as well as ground crew. Many of them came from the Navy.
Factual errors: Carl Schell looked a little old to play Manfred Von Richthofen. The real "Red Baron" was only 25 when he was killed on 21 April 1918.
Errors in geography: When Stachel is brought to Berlin, establishing shots of his entrance into the city are instead unmistakably set in Dublin, Ireland. This includes clear unobstructed views of Christchurch Cathedral, The Four Courts, and the courtyard of Trinity College Dublin (with the campanile, The GMB, the Dining hall, with the cars occupants finally disembarking in front of and entering the chapel.)
Revealing mistakes: Just before Stachel and Willi fly under the bridge, the facial shots of George Peppard show the aircraft's elevator raised. This would result in a nose high attitude, continuing round in a loop. The external shots show him flying straight and level.
Errors made by characters (possibly deliberate errors by the filmmakers): While serving as an infantryman at the beginning of the movie, Stachel's rank insignia clearly indicates that he was a sergeant (Feldwebel). But years later, when he reports to his new flying unit after pilot training, he tells his commanding officer that he was a corporal (Unterofficier).
Errors made by characters (possibly deliberate errors by the filmmakers): After arriving at his new air station, Lieutenant Stachel is interviewed by his squadron's commanding officer (CO). While looking through Stachel's personnel record, the CO asks him what rank he had attained in the infantry. This was a needless question, since Stachel's record would clearly have shown all ranks he had previously held.
Factual errors: In the Blue Max, when the film starts they are flying "worn out" Pfalz D.III and Fokker D.VII types. The NEW aircraft are Fokker Dr.I types. In reality the Pfalz D.III and the Fokker Dr.I entered service about the same time in the fall of 1917, they would have been the old and worn out planes in 1918 with the NEW aircraft being the Fokker D.VII, Ironically this sequence is correct in the book version of the movie.