Suggestions that there may never have been any drones at Gatwick were down to “poor communications”, police have said.
Ministers were briefed on the latest situation at the airport in a conference call amid growing criticism of the handling of investigation by Sussex Police.
The 47-year-old man and a 54-year-old woman were arrested on Friday after a tip-off from a member of the public, while their house in nearby Crawley was searched.
They are no longer suspects, say police, who insists investigations are “not back to square one.”
Gatwick Airport has offered a £50,000 reward, via Crimestoppers, and another £10,000 has been put up by the charity’s chairman Lord Ashcroft to catch the culprits responsible for the chaos, which grounded or delayed around 140,000 passengers.
Detective Chief Superintendent Jason Tingley said he hoped the money would persuade someone to come forward with the vital clue.
“We are actively investigating sightings of drone activity at Gatwick Airport following 67 reports from the evening of December 19 to December 21 from the public, passengers, police officers and staff at the airport,” he said.
“We are interviewing those who have reported these sightings, are carrying out extensive house-to-house enquiries and carrying out a forensic examination of a damaged drone found near the perimeter of the airport near Horley, which is close to the last reported sighting.”
DCI Tingley revealed that there were some “persons of interest”, but would not say if police were close to making any further arrests.
Around 1,000 flights were cancelled or diverted after drones were spotted inside the perimeter of the UK’s second biggest airport on Wednesday.
Mr Tingley said there is no video footage available and investigators are relying on 67 drone sightings by multiple witnesses.
When asked about speculation there was never a drone, he said: “Of course, that’s a possibility. We are working with human beings saying they have seen something.”
Mr Tingley said police were running a three-pronged investigation including working through information relating to “persons of interest”, investigating sightings and forensically examining the damaged drone, which was spotted by a member of the public.
He explained the examination could be hampered by the wet weather on Friday and Saturday, which could have washed away evidence.
And he could not rule out the risk the culprits would strike again at Gatwick or another airport.
“Someone, somewhere knows either the perpetrator or perpetrators responsible for this, or has information relating to these incidents,” he said.
“But secondly, our tactical response, should there be any more drone sightings, is still in place.”