Ash clouds.
What we need are some Drones to fly into the ash clouds. To find out the composition density position of the ash. I dornier with sensors is not enough.
A few flights by interested airines without proper sensors is all showmanship.
Also we need some research into the effects of ash on engines, airframes,pitot systems etc.
By doing this we can find out which levels are harmful to Aviation. At present the powers that be are taking the safest route.