"Would it not be easy to send up a police/military drone to follow the errant drone "
First, find your drone - If there _IS_ a drone.
The only "drone strike" in London airspace turned out to be a plastic bag.
It's rather telling that these "drones" only came out at twilight/after dark.
"Picture this: it’s late in the evening on a freezing cold, dark, and windy December night in southern England, and an airport worker at Gatwick — London’s second international airport — sees something fly past in the gloom above the floodlights. The weather and darkness makes it difficult to see what the object was, but the report is phoned in to security. What was it? A flock of birds? A piece of plastic litter caught by the wind and blown through the night? In this case, the call is recorded as a drone. Because the magic D-word has been uttered, a security plan swings into action, the airport is put on a high state of readiness, and flights are suspended.
Thousands of people across the site are put on alert, watching for the drone. And of course, the drone reports roll in, and the story takes on a life of its own. People who have no idea what a drone looks like in the air are now expecting to see one, so of course when a flock of birds or a plastic bag caught by the wind crosses their peripheral vision they too are convinced that it is the drone. Night turns into day, there is a lull in the reports so the airport re-opens, only to be closed again following a fresh spate of sightings. Flights are diverted all across the country, and tens of thousands of passengers are stranded in the terminals."
- A drone large enough to actually _cause_ a problem would show up on radar.
- A drone large enough to not be knocked out of the air by wake turbulence from the _previous_ aircraft would show up on radar
- The increase in the number of drone sightings reported by airline pilots is almost exactly matched by the DECREASE in the number of bird sightings reported by airline pilots.
If you whiz past something the size of a DJI Phantom(*) at 180-200mph(**), are you going to be able to give a detailed description of it? I hit a duck flying out of an airstrip at 70mph and the only inkling I had was a flash of one of its flockmates dodging my propellor as I heard the thump of it hitting my wing (The only reason I knew it was a duck was the 1/20 second sillouette and the only reason we know it was a mallard was the green feathers left behind in the rivets)
(*) Which is a HELL of a lot smaller than a flying mallard duck!
(**) normal approach speeds. Watch some landing videos. There are a few with birdstrikes in them. The pilots _never_ see the birds and you can barely see them in frame-by-frame replays.