London's Heathrow airport had to suspend flights on Tuesday after drone sightings there, following similar disruptive incidents at Gatwick in December that affected 1,000 flights.

The move to suspend flights is understandable. Airports and the airlines that pay them don't want to see a drone sucked into a jetliner's engine, or a drone that's rigged as an explosive device wreaking havoc.

But it seems absurd that a couple of $500 drones and some rogue pilots can disrupt millions of dollars of business by causing flight delays and negative experiences for travelers.

With so much at stake — in terms of safety and profits — why aren't airports better prepared to deal with drones?

It's not for lack of technology, said Lance Sherry, director of the Center for Air Transportation Systems Research at George Mason University.

"Counter drone" systems are already on the market, though they are not perfect and are constantly evolving, he said. They employ high-resolution radar and other sensors to detect drones. Some use lasers, ballistics, nets and signal jammers to intercept and take drones down as needed.