Police and military forces were involved in the response, Britain’s aviation minister Liz Sugg said. Sussex police said the drones were of an “industrial specification,” rather than a toy or amateur unmanned aircraft.
The incident, at Gatwick Airport—Britain’s busiest after London’s Heathrow—amplifies concerns about the threat to commercial flights from unmanned aircraft.
The drone flights near the airport began late Wednesday and continued into Thursday, the airport operator said. Some flights, including to the U.S., were grounded and others diverted to land at other airports, stranding, diverting or delaying tens of thousands of passengers in the run-up to the busy holiday travel period.
The disruption comes a week after authorities in Mexico started investigating a possible collision between a drone and a Boeing 737 jetliner. The Aeromexico flight sustained damage to the nose on landing, though the plane landed safely.
Air safety authorities have become increasingly concerned about the rapid growth in the use of commercial drones, often as toys. The U.S. Federal Aviation Administration now tracks more than 1,000 suspected incidents of near misses by planes and unmanned aircraft a year. Some of those reports turn out to be spurious.
The risk has created growing demand for systems to protect against such incursions, including from the military. Some of these systems use radar or acoustic sensors to spot the drones. Others are designed to force a drone to land. Governments also have pressed drone makers to install systems on their equipment that bars them from flying in protected airspace, such as airports and military installations.
At Gatwick, flight operations were halted Wednesday at 9:03 p.m. local time after two drone sightings were reported. The facility reopened at 3:01 a.m. Thursday before closing less than 45 minutes later because of renewed concerns about drone flights around the airfield.
Britain’s Civil Aviation Authority on Thursday said it was “totally unacceptable” to operate drones near an airport. In the U.K., it is illegal to operate a drone within 1 kilometer (0.62 miles) of an airport or at an altitude above 400 feet. Those flying the drones illegally could face a five-year prison sentence, Ms. Sugg said.
The concern about drone often increases around the holiday season, when they are often bought as presents.
In November, a British man was fined and had to forfeit his drone after a court ruled the unmanned aircraft was flown too close to a police helicopter. But this was a rare success for authorities who often struggle to apprehend and prosecute drone operators.
Pilot groups have become increasingly vocal about the risks to flights and passenger safety.
“Even two kilograms of metal and plastic, including the battery, hitting an aircraft windscreen or engine or a helicopter tail rotor, could be catastrophic,” Rob Hunter, the head of flight safety at the British Airline Pilots’ Association said earlier in December.