The Thunderbirds' 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.
Only two episodes were made in which Virgil's vehicle, Thunderbird Two, was not involved in the story's primary rescue - "Terror In New York City" and "The Imposters". "Terror In NYC"'s non-use of Thunderbird Two was forced because the episode was originally made as a half-hour show; when Sir Lew Grade of ITC demanded the series be remade in one-hour format, AP Films had writer Alan Fennell write in the subplot where Thunderbird Two is mistaken for an enemy bomber and attacked by a US warship; ironically, this helped make the episode the one most fondly remembered by original fans of the show. It also explains why this episode needed two directors (David Elliott and David Lane).
When the launch sequence of Thunderbird 2 was shot, pilot Virgil Tracy was shown being taken to the craft in civilian clothing. When the completed sequence was cut together, he was seen to have mysteriously gained a uniform. To provide continuity, a scene was later shot and added showing his uniform appearing in the cockpit.
According to "Guinness World Records 2008", the character of Jeff Tracy holds the record for the "Highest Earning TV Character", said to be worth an estimated $US50 billion; assets included maintenance of Tracy Island, all the Thunderbird machines, and so on.
Season 2 is only 6 episodes because ITV canceled the series when they were unable to gain wide US release. This would have been the only way to afford to produce such an expensive 1 hour series. They tried to show it in the US as two 30 minute episodes vs the 1 hour episodes as shot. Oddly, when shown in Los Angeles, it was shown in the late 60's on independent stations KTTV and later on KHJ as two back to back 30 minute episodes. This completely negated the need of splitting the original 1 hour episodes into 2 30 minute episodes.
Three Thunderbirds story scripts originally owned by Alan Pattillo ("The Cham-Cham", "Give Or Take A Million" and "Alias Mr. Hackenbacker"), were sold at auction in Melbourne, Australia, for AU$150.00 each on 12 August 1990.
It was while the Round House (through which Thunderbird 3 would be launched) that Derek Meddings realized that the design of the building was just right for Thunderbird 5, the International Rescue space station. Unable to come up with a convincing design before now, this was the last of the five Thunderbird craft that he created. By adding aerials and transmitters to the Round House, he developed the series' most unusual and effective vehicle, although it was to play only a minor part in the finished program.
Some of the guest characters were named after real people. For example: Lt. Bob Meddings (seen in the episodes "Trapped In The Sky") was named after Art Director Bob Bell and visual effects supervisor Derek Meddings. Dr. Korda (seen in the episode "Day Of Disaster") was named after Hungarian-born film producer/director Sir Alexander Korda; Lady Penelope's alter ego Wanda Lamour (from the episode "The Cham-Cham") was named after puppeteer Wanda Brown (née Wanda Webb).
The Hood has never been referred to by any name on all but two episodes - "Martian Invasion", where he calls himself Agent 79 in his transmissions to General X, and "Edge Of Impact", where he gives his codename as "671" when he contacts General Bron. "Edge of Impact" is also the only episode in which we see the Hood acting with motives not involving International Rescue.
Before recording for the second season was due to commence, David Holliday, the original voice of Virgil, had relocated to the United States, so Jeremy Wilkin replaced Holliday as the voice of Virgil for the second season and the two Thunderbirds movies Thunderbirds Are GO (1966) and Thunderbird 6 (1968).
John Tracy's character design and mannerisms were a slightly altered redesign of Lt. Fisher from Stingray (1964). Gerry Anderson claims to have disliked the character's "all-American" quality, among numerous other reasons he has cited over the years, which is why John is so rarely seen in the series.
According to Shigeru Miyamoto, famous video game creator, Thunderbirds served as a huge inspiration to a video game franchise he created called StarFox, to the point that the box art of the first game was a photo of puppet versions of the characters in the game.
Richard Branson is a great fan of the series and has named a fleet of rescue locomotives for Virgin Trains after the Thunderbirds craft. During one of Sylvia Anderson's many transatlantic trips, she was travelling in a Virgin plane named after Lady Penelope. Unfortunately, the plane broke down and there was a long delay in LA. Mr. Branson did, however, give Sylvia complementary mileage for the delay.
F.A.B stood for "Full Acknowledgement and Briefed." Gerry Anderson, the producer of the show was known for these obscure catch phrases these include P.W.O.R from Stingray (1964)(Proceeding With Order Received) and S.I.G (Spectrum Is Green") from Captain Scarlet and the Mysterons (1967). They all stand for "ten-four", "I copy" and "roger that".
The interlude music in this (British) series and some of the interlude music in the album "Days of Future Passed" are hauntingly similar. One could deduce that at least some members of British band The Moody Blues were fans of the show.
The trivia item below may give away important plot points.
By the finale of the series and film "Thunderbird 6," Lady Penelope has lost both her famous car and her yacht. Parker gambled away FAB 2 in "The Man From MI 5", and FAB 1 was destroyed in the crash of Skyship One at the end of the second feature film Thunderbird 6 (1968).