LONDON -- When drones buzzing over the runway forced London's busy Gatwick Airport to shut down, many travelers wondered why it's so hard for authorities to stop such intruders.
Shoot them down, some said. Jam their signals, others suggested.
Experts say it's not that easy.
The number of close calls between drones and aircraft has increased dramatically in recent years as the popularity of drones has soared. Basic models for amateurs sell for under $100; larger, more sophisticated ones can cost hundreds more.
Authorities have been warning for years about the risk of a disastrous collision between a drone and an airliner. A drone could get sucked into a jet engine or crash through a windshield, injuring the pilot.