Trivia

The flying sequences under the direction of Anthony Squire, were based at the Vickers aerodrome at Chilbolton near Nether Wallop in Hampshire. Squire managed to secure one of the last airworthy Avro Lancaster bombers for the task. The cameramen were positioned in the front and rear turrets while Squire conducted proceedings from the central astrodome. The Lancaster was replaced by a Vickers Valetta after all the crew except Squire fell asleep due to an oxygen supply failure. Luckily as he recalled, "They all woke up on the way down, like people in a fairy wood, but I didn't bother with the Lancaster again."

The film refers to control-reversal above the sound barrier: that the pilot must push the stick forwards to make the plane climb. This is not a universal aerodynamic phenomenon that applies to all supersonic airplanes and was only a quirk of early ones which had insufficient tailplane stiffness, so the elevators (which control climbing and descent) act as though they were trim tabs, twisting the tailplane to produce an aerodynamic effect opposite to that intended. It is control-reversal which Chuck Yeager referred to when he said that any pilot who tried it in other supersonic planes would have been killed.

When Tony and Susan return from Cairo, it can clearly be seen that the Comet that they fly in has rectangular windows. Extensive redesign after crashes in 1954 - due to metal fatigue - included the windows being changed to an oval shape.

The Vickers-Supermarine Swift, called the "Prometheus" in this movie, is not capable of supersonic flight.

Despite this fictionalized story of breaking the sound barrier, this feat was accomplished by U.S. Air Force General Chuck Yeager on October 14, 1947 at Edwards Air Force Base. Furthermore, Yeager explained that if a pilot were to break the sound barrier in the manner depicted in this movie (using control-reversal), he would have been killed. This movie was also heavily based on the endeavors of the de Havilland company in the U.K. Geoffrey de Havilland, Jr., son of company owner Geoffrey de Havilland, was killed in September 1946 while conducting high speed tests approaching the speed of sound over the Thames estuary.