Thousands of passengers remain stranded at Gatwick as police continue their search for the operator of a drone that has caused the airport to shut down.
Flights were brought to a standstill after a drone was seen over the airfield on Wednesday.
Police have so far failed to locate the device or its pilot, but are considering plans to shoot it down.
Gatwick’s bosses have urged those due to travel to check their flight status before turning up at the airport.
They say they are working to introduce “a limited number of flights” over the coming hours.
- Drones ruin honeymoon and ‘final’ granny trip
- How can a drone cause so much chaos?
- Gatwick Airport disruption: Your rights
Speaking on Thursday, Gatwick’s chief operating officer Chris Woodroofe said 120,000 people had been due to fly out since the runway closed.
Staff were working on contingency plans in the event of flights being grounded again, he said.
Passengers have complained of “freezing” temperatures in the south terminal, while others found themselves stuck abroad after inbound flights were either cancelled or diverted.
Dozens of passengers contacted the BBC to say uncertainty had led them to ditch their festive travel plans or spend extra money on new flights and hotel stays.
Budget airline Ryanair said it was switching all of its Gatwick flights to operate in and out of Stansted airport on Friday.
Transport Secretary Chris Grayling said the government was doing “everything we can to make arrangements with other airports”.
Among the measures was the lifting of night-flight restrictions so that “more planes can get into and out of the country”, he said.
What has happened?
- Gatwick’s runway closed just after 21:00 GMT on Wednesday when two drones were spotted flying over the perimeter fence and into the airfield
- It briefly reopened at 03:01 on Thursday but was closed again about 45 minutes later due to further sightings
- Outbound flights were grounded, while incoming planes were redirected to other airports
- About 10,000 passengers were affected overnight on Wednesday
- On Thursday, police said the drone flight was “a deliberate act to disrupt the airport” but there was no evidence to suggest it was terror-related
- More than 20 police units from two forces joined the search for the perpetrator, who could face up to five years in jail
- The military, with “a range of unique capabilities”, was deployed to assist the police operation
- By Thursday night, police said there had been more than 50 sightings of the drone since the runway was first closed
The search for the drone
Sussex Police has been locked in a game of cat and mouse with the drone since the airport shutdown began.
Despite dozens of sightings, the device, which detectives believe to have been “adapted and developed” to cause deliberate disruption, has not been found.
Det Ch Supt Jason Tingley said police were re-evaluating plans for armed officers to shoot the drone down after other methods failed.
The measure was initially dismissed over the risk posed by “stray bullets”, but became a “tactical option” again after other methods failed, the detective said.
Officers were also following lines of inquiry into “particular groups” and a “number of persons of interest”.
“We will do what we can to take that drone out of the sky,” he said.
Supt Justin Burtenshaw, head of armed policing for Sussex and Surrey, said finding the drone’s operator was “a difficult and challenging” prospect.
“Each time we believe we get close to the operator, the drone disappears; when we look to reopen the airfield, the drone reappears,” he said.
As a result of an appeal for information, Sussex Police said it had been inundated with calls, but urged people to contact with information “focussed on the identity or location of the drone operator”.
What has happened to passengers?
Travellers have found themselves unable to fly in and out of Gatwick.
Thousands have been left stranded for hours inside the airport’s terminal building, resorting to sleeping on floors and benches.
Some who spoke to the BBC included a couple hoping to honeymoon in New York and a seven-year-old who had been due to fly to Lapland.
Others have found themselves stuck abroad.
Earlier this week, Gatwick predicted a “record-breaking” festive period, with tens of thousands of passengers expected most days.
Airport chief Mr Woodroofe refused to comment on the possibility of those affected by the chaos being awarded compensation.
The Civil Aviation Authority said it considered the event to be an “extraordinary circumstance”, and therefore airlines were not obligated to pay any financial compensation to passengers.
Alex Neill, from consumer rights group Which?, said people “may still be entitled to meals, refreshments, hotel accommodation or transfers”.
Airports and drones: The law
It is illegal to fly a drone within 1km of an airport or airfield boundary and flying above 400ft (120m) – which increases the risk of a collision with a manned aircraft – is also banned.
Endangering the safety of an aircraft is a criminal offence which can carry a prison sentence of five years.
The number of aircraft incidents involving drones has grown dramatically in the past few years, as the popularity of the devices has increased.
In 2013 there were zero incidents, compared to almost 100 last year.
Mr Grayling said the events at Gatwick are “not something that’s not been experienced in this country before”, even though drones have been a problem elsewhere in the world.
The government was now looking to “go further” with drone-control, he said, including considering age-limits for users.
He added: “Anyone who tries to do the same [as at Gatwick] again, should expect to go to jail for a long time.”
The UK Airprox Board assesses incidents involving drones and keeps a log of all reports.
In one incident last year, for example, a pilot flying over Manchester saw a red “football-sized” drone passing down the left hand side of the aircraft.
In another, a plane leaving Glasgow narrowly missed a drone. The pilot in that case said the crew only had three seconds of warning and there was “no time to take avoiding action”.