Although Supercar (1961) had been shown in syndication, this was the first Gerry Anderson "Supermarionation" series to appear on US network television (NBC, on Saturday mornings, between 1963 and 1965).
In spite of the ingenuity that went into creating the models, the designers also owed a debt to their local Woolworth's. Derek Meddings and his team of designers were regular customers of the 'Woolies' store in Slough, where they bought up packets and packets of Airfix kits which were then dissected into bits and pieces and used to make their own designs more interesting.
Footage was reused throughout the series. For example, whenever Fireball Jr. detaches from the main XL5 unit and reattaches, it's always the same close-up shot.