“[The drone pilot] knew the blind spots for it, where it could not be ‘hit’. It was clearly someone with really good knowledge of Gatwick, someone who had worked there. Hypothetically it could have been a disgruntled employee,” the source said, as quoted by The Times newspaper.
According to the media, the drone was flying in blind spot areas that were known only to the airport's employees, and the hypothesis was supported by another source, who said that the incident might have been staged by a "disgruntled employee."
Flights were temporarily shut down again on the afternoon of 21 December after the drone was spotted again. The incident led to the cancellation of 1,000 flights and affected about 140,000 passengers. The UK Sussex Police detained two people in connection with the incident but released them shortly thereafter after being unable to prove their involvement in the incidents.