Thunderbirds is very popular with real-world scientists, inventors and engineers, much to creator Gerry Anderson's own surprise. Gerry had an interest in aircraft from his boyhood days as his brother Lionel was a pilot in the Royal Air Force (RAF) during World War II. This interest took him to Feltham, England, where the Supersonic Aircraft "Concorde" was being built. A design engineer gave Anderson a tour of the facility. "I was dreading that he would ask me what work I did" recalled Anderson, "because here was state-of-the-art aircraft, supersonic, and here I was, a filmmaker of puppet shows." The engineer did, indeed, ask Anderson what he did for a living, but he remained evasive until he finally offered only that he was in film business and finally later that he was a producer. The engineer persisted. "Finally I mumbled Thunderbirds" says Anderson. The response was electric. "I was told. 'Don't move!' He ran upstairs and all of the designers came down with him. They talked with me for an hour. All of them were fans. They even had a theory that Thunderbird 2 would fly if it were built. Quite amazing. I thought they would all sort of laugh." When the Concorde made its maiden flight to Toulouse, France, to be unveiled, it was greeted by the Band of the Royal Marines striking up Barry Gray's Thunderbirds March.
International Rescues' radio code "F-A-B", meaning "message received and understood", didn't stand for anything, it was just supposed to sound "hip". In fact, when asked what it stood for, Gerry Anderson once replied, with some bemusement, "Fab," as though it were obvious. Later, due in part to fan-submitted stories, F-A-B came to mean Fully Advised and Briefed, in keeping with P-W-O-R (Proceeding With Orders Received), a similar radio confirmation code in the series Stingray (1964).
Gerry Anderson would take the sets/props/etc. and have them "dirtied up" and made to look worn and damaged before filming, giving them a more realistic appearance. This technique was later used extensively by George Lucas in Star Wars: Épisode IV - Un nouvel espoir (1977).
The faces of the Tracy family members were composites of those of famous celebrities of the day:
- Jeff Tracy was modeled upon actor Lorne Greene of Bonanza (1959) fame.
- Scott Tracy was modeled upon actor Sean Connery, who stared in the early James Bond films.
- Alan Tracy was modeled upon actor Robert Reed of Les accusés (1961).
- John Tracy was modeled after British pop singer Adam Faith and Hollywood actor Charlton Heston.
The five Tracy brothers were named after five of the NASA astronauts from the "Mercury Seven" space program from the early 1960's:
- Scott Tracy after Scott Carpenter.
- Virgil Tracy after Gus Grissom whose real first name was Virgil.
- Alan Tracy after Alan Shepard.
- Gordon Tracy after Gordon Cooper.
- John Tracy after John Glenn.