Chameleon Tours was marketed as a Gatwick Airport-based business offering budget package holidays to Europe for young people between the ages of 18 and 25.
However, Chameleon Tours was actually a front for the Chameleons, who abducted the humans, took them in aeroplanes to their space station, then miniaturised and placed them in suspended animation. Samantha Briggs hired Inspector Gascoigne to investigate them when her brother went on a Chameleon Tour to Rome and disappeared.
The Second Doctor and Jamie McCrimmon helped her and exposed the Chameleons' operation. (TV: The Faceless Ones)