Factual error: Terry-Thomas's plane gets stuck between the carriages of a Paris-bound train (in fact filmed on the single-line track between Bedford and Hitchin). Just before the train plus plane goes into a tunnel you can see the cooling towers of Bedford's Goldington Power Station (circa 1960) behind TT's head. (01:58:20)
Other mistake: At the two-hour point when Terry-Thomas' plane lands on the moving train a nuclear power plant can be seen in the background several times. (02:04:38 - 02:05:02)
Factual error: The "American" aircraft is really a British design called a Bristol Boxkite.
Suggested correction: Why is this an error? The "American" aircraft was fictional (there was no such thing as the "Phoenix Flyer") so they could have used anything to represent it. The design they used was known to work and was safe. The original Boxkite was actually a British version of The Farman and was similar in appearance the the American Curtiss.
The American pilot, while talking to the movie's heroine, states that his plane is a Curtiss. Check the scene in the restaurant, the night before he saves the German plane with the damaged tail. I tend to think the "Phoenix Flyer" was the name of that individual plane, and not the model of aircraft. That would mean that the pilot of the plane indirectly said that his plane was of American manufacture, as Curtiss was an American company.
Another interesting note is that in the scene with the runaway German plane, Orville Newton's plane is being wheeled out of the hangar, which has a "Bristol Company" sign over the doors. They "just happen" to be borrowing space in the hangar owned by the company that made the original Bristol Boxkites! It's a meaningless detail, but fun that they arranged it that way.
Continuity mistake: When the German colonel crash lands in the Channel, he first hangs directly under his upside-down plane before he has to let go, and the plane zooms in a straight line away from him. But as he resurfaces in the foreground, the plane comes in from the background's left before landing in the water.
Continuity mistake: The number of tail fins on the "American" aircraft changes from two to three depending on the shot.
Continuity mistake: In some scenes the "Antoinette" flown by the British flyer has authentic, thin "wing warping" wings. In other scenes it has thick modern glider wings with ailerons. This was done because the authentic machine wasn't very airworthy and was modified during the shooting.
Other mistake: The Japanese plane and the German plane are actually the same aircraft type, a British Design called an "Eardly Billing." The "Japanese" version is re-dressed with canvas partitions between the wings, painted dragons, etc, the "German" has no canvas and German eagles, but they are the same machine.
Other mistake: As the planes go over Dover you get a very nice view of the modern harbour complete with cross Channel ferries and oil tanker.
Revealing mistake: When the tail breaks off of the "German" machine and it careens around the field, you can see the little steerable tail wheel used to control the plane in those scenes. In all other scenes this plane has a tail skid.
Plot hole: Before the race starts, Sir Percy intends to sabotage some of the other fliers. He announces to Courtney that he had lured Dubois away by giving him the address of Courtney's daughter, but later, when the race starts, there is nothing wrong with Dubois' machine even though Sir Percy had the chance.
Continuity mistake: When Sir Percy attempts to spy the other fliers from the hangar roof, he uses a ladder to get to the top. But when Dubois startles him and he slides off the roof, the ladder on the roof slope is gone.
Continuity mistake: When Gerd Fröbe is teaching the new pilot, a car is approaching and the pilot crashes vertically through the bottom of the plane. In the first shot his vest is up and in the return shot his vest is down, still stuck in the plane.
Factual error: Just before the planes start to cross the channel, we have a scene of a reporter with some British soldiers. They wear the cap and collar badges of the Royal Corps of Signals, which wasn't formed until 1920 - 10 years after the film is set.
Factual error: Whilst Newton is trying to fix the wing spar they fly over a Land Rover parked at the back of the hangers.
Other mistake: When Stuart Whitman asks to borrow a monkey wrench from James Fox, Fox hands him a pipe wrench, a very different tool.
Suggested correction: This is not a mistake for two quite plausible reasons. First, the two flyers are the principal rivals in the race and it would be quite in character for one to try to impede the other by substituting a tool inferior to the one requested. Second, the Monkey wrench and the Pipe wrench are similar in appearance and function. The pipe wrench may have worked. Also, Wikipedia says: The term monkey wrench is also sometimes used loosely, usually by non-tradespeople, to refer to the pipe wrench."
Continuity mistake: When Stuart Whitman is attempting to fix a broken left wing spar on his aircraft with Sarah Miles at the controls, in one long-wide shot, Whitman suddenly appears on the right wing and then in the next shot, he's back on the left wing.
Continuity mistake: The Avro Triplane goes back and forth between using the authentic four-blade metal-and plywood propeller from the era and a two-blade massive wood propeller. The reason is, the producers originally tried to use the historic designs as much as possible, but had to change some things in the course of the shooting because the originals proved to be not airworthy enough.
Factual error: The British pilot takes off in his Avro Triplane even though the American pilot hangs from his tail. By our modern standards, the planes of this era would be considered ultralights. The weight of a human hanging from its tail would put any ultralight so badly out of trim that it would stall instantly, even assuming it could handle the extra weight of a second person at all.
