Doctor Who The Faceless Ones by Terrance Dicks

This source details a science fiction narrative where the Doctor, along with his companions Jamie, Polly, and Ben, arrive unexpectedly at Gatwick Airport in 1966, causing immediate disruption. They quickly become entangled in a mystery involving Chameleon Tours, an airline secretly abducting young people. The companions eventually discover that faceless aliens are impersonating humans and using the tours to transport their victims to a space station for unknown purposes. The Doctor and his friends must then work to expose the aliens, rescue the abducted individuals, and escape the dangerous situation before they too become victims.