Tonnes of thick ash that spewed into the atmosphere after Iceland's Eyjafjallajokull volcano erupted in 2010 cost the airline industry an estimated £1bn, it has emerged.
Superheated ash particles turn into glass when they pass through jet engines, and can cause planes to crash.
As you'd expect, air traffic officials prefer to avoid this.
But while ash can be deadly, it turns out that planes can fly fairly close to ash with little-to-no impact if the density is low enough.
And it's not surprising that the prospect of a machine allowing planes to detect whether or not it's safe to fly during an eruption is receiving such an enthusiastic welcome.
Known as AVOID (Airborne Volcanic Object Imaging Detector), the device, funded by Easyjet and developed by Dr Fred Prata of the Norwegian Institute For Air Research, uses an infra-red camera to check the position and density of ash clouds.
Using the gizmo, a pilot can see ash clouds up to 300km ahead at altitudes up to 50,000ft.
The relatively small, orange machine can also measure the density of ash and detect safe 'corridors' through which planes can fly.
Combined with satellite imaging technology, the result could be a lot less cancelled flights.
"This device can be used in a tactical sense to let the pilot see the hazard and fly safely around it," Dr Prata said.
More than 10,000 flights were cancelled and 10 million passengers were affected by the 2010 eruption, the International Air Transport Association claims, because air space officials were forced to assume the ash was evenly distributed over an enormous area.
But Easyjet says its research demonstrates that ash actually travels in 'clumps' - and that if you can detect where the ash is concentrated you can simply redirect plane routes to avoid them.
The airline claims that most of the airspace cancelled in 2010 would have been left open had the device been available.
It's still early days for the new technology, however. So far the device has only been trailed on small aircraft flying near to Mount Etna in Sicily, at altitudes up to 12,000 feet.
There are talks to start trials on large A340 planes from next year and to fit the devices to commercial jets by the summer, but as yet the device is unproven.
And time could be running out.
The BBC recently reported that the Icelandic volcano Katla has recently been emitting harmonic tremors that indicate movements of magma below the surface, and an imminent eruption.
In the past Katla, which is much larger than Eyjafjallajokull, erupts with intense violence. In the relatively recent past it has been responsible for ash clouds on a scale large enough to cause global food production problems.
The flood discharge at the peak its 1755 eruption was equivalent to the average discharge of the Amazon, Nile and Mississippi rivers.
Worse still, all three times that Eyjafjallajokull has erupted in the past 1,000 years Katla has followed with its own eruption soon after.
So for now, at least, we remain at the mercy of the movement of Icelandic tectonic plates.