Sir Percy climbs to top of the roof of a building to spy on the fliers by scaling a ladder that is laying on the roof. But when he slides off the roof, the ladder under him is gone.
The race numbers on some of the radio-controlled models are different than the numbers on the full-size airplanes they represent.
On the first day of the race from London to Dover, Ponticelli doesn't take off with goggles or has them when he makes the emergency landing. However when he flies over Mays when he is being helped by the elderly couple on the road and looks down on them he is wearing goggles. They disappear again in the next scene when he starts singing.
The configuration of several aircraft changes from shot to shot. This includes the Bristol Boxkite which, in some scenes has two rudders and in others has three. The Antoinette is changed the most. In close ups it has thin "wing warping" wings. In others it has thick modern glider wings with ailerons with redundant support wires added. These changes occurred when it became clear that the accurate replicas of 1910 flying machines, originally built were not airworthy enough. Details are provided in Allen Wheeler's book "Building Aeroplanes for Those Magnificent Men."
The purple touring car, in which Ponticelli and his wife and children arrive at the lookout tower at the airfield, has green-spoke-rims. When we next see the family and the car at Ponticelli's hangar it now has yellow-spoke-rims.
Richard Mays is supposed to be in the Coldstream Guards. However, his tunic's buttons are not arranged in pairs, but appear singly like a Grenadier's.
As the fliers approach Paris, the subtitles state that the music being played is the "Can-Can" - presumably intending to refer to the piece from "Orpheus in the Underworld" by Jacques Offenbach. In fact the music is not French at all - it's the "Tritsch-Tratsch-Polka" by Johann Strauss II.
Newton supposedly loses his trousers after using his belt to repair a wing strut. It is impossible for trousers to fall off over boots.
The Germans are introduced with the song "Deutschland, Deutschland über alles" ("Einigkeit und Recht und Freiheit") which became the national anthem in 1922. In 1910, the imperial anthem "Heil dir im Siegerkranz" had the same melody as Britain's "God Save the King" and America's "My Country Tis of Thee." However, "Deutschland" was already a well-known song, and in any case it is heard by the audience, not the characters. This distinctly German song is a deliberate choice for the scene, as playing the "God Save" melody for Germans would be extremely confusing to a modern audience.
When Dubois 'buzzes' Fire Chief Perkins in the windmill, the long shot shows a double sitting in Perkins' chair.
Close inspection in many scenes reveals that the "sky" in the background of some scenes is a backdrop, with many visible seams and lines in it.
When the Japanese kite fliers land, you can see the wires suspending them.
As Ware-Armitage manoeuvres his way back in to the seat after shooing the bird by throwing a bottle at it, he jiggles the airplane controls forward and backward considerably. However, there is no change to the plane's flight path.
In the scene where Sir Percy is on top of the train, there are power plant cooling towers in the background.
At several points in Sir Percy's train scene, you can see post-1924 cooling towers in the background.
When Orvil is out on the wing of the Bristol Boxkite, fixing the broken strut, it flies along the back of the hangars, where three 1960s vehicles are parked, including a short-wheelbase Land Rover.
1960s ferries are visible in Dover Harbor when the competitors go for a swim in the sea at Dover and later as the planes fly over the white cliffs.
When Sir Percy is on top of the train, in the background you can see the cooling towers of a nuclear power plant.
Examples of 1960s architecture are visible in the back-projection during the over-flight of Paris.
When Ponticelli climbs onto Newton's aircraft in flight, the stunt double performing the action has devices attached to his gloves to make gripping the landing skids much more secure.
When Orvil crash-lands at Dover, bags of white powder (used to create dust as he lands) are seen attached to his landing struts.
The locomotive pulling the train that Sir Percy lands on is actually Scottish. It's Highland Railway No 103 of 1894, the only surviving Highland Railway locomotive, and is now on static display in Glasgow Museum of Transport.
Sir Percy flies at a very low altitude and is overtaken by a train but the train driver does not see him.
Both in the Daily Post board room and at the Japanese flying school, there are several models of the planes used throughout the film. It is unlikely they would have known what planes would appear at the race beforehand - especially the Italian plane, as it was a last-minute arrival on the day of the race.
When Orvil and Patricia stop for a bite to eat in the cafe she asks about the type of aeroplane he flies. He says that it's a Curtiss with an Anzani engine. In fact, his aeroplane is a Bristol Boxkite which itself was a British derivative of the French Farman biplane of 1909.
Orvil Newton refers to his plane as a "Curtis", which was an actual American pusher biplane of the time, but in fact his character is flying a British machine in the film, namely a Bristol Boxkite.
When talking about the Japanese pilot behind his back, one of the other pilots makes a reference to chop suey. Chop suey is a Chinese dish, not Japanese.