Pilots reported 39 drone sightings from their planes in the first five months of 2016, a dramatic increase on last year, according to new figures.

The ILF Environment and Transport Inspectorate said 31 of these drones – flown for fun by members of the public – were spotted at airports and 24 at Schiphol. Of the 39 reports, 35 were drones and four were model aircraft.

In the whole of 2015, just 15 drones were reported and there are concerns about safety and collisions with planes, which fly so fast that the impact of any small crash would be greater.

The increasing numbers spotted are, reports NOS, probably due to technically more advanced drones. Anybody can buy and fly these, but it is not permitted to fly an unmanned craft on or near an airport.

Recently, one drone was spotted at a height of 5,000 metres, and two house roofs and a car have been damaged by drones; up till now, though, there have been no reported collisions involving people.

The Dutch Airline Pilots Association, the VNV, is calling for stricter European rules, technical limitations so drones cannot fly higher than 50 metres, and a proactive approach. ‘They are waiting until something goes wrong,’ a spokesperson told NOS.

People who want to fly a drone for professional purposes need a permit, and there are about 200 registered drones in the Netherlands.