So why not fly under it?
By taxiing along the highways, I suppose.
In fact has any one noticed that all the pictures of the closed airports looks cavok to me??
Well, you're clever, aren't you!
Congratulations for noticing. Did you expect to see a black sky or something?
The fact that you can look through it to see the blue sky doesn't mean there's nothing there - as has just been shown by test flights (with test results) and military aircraft (with damage on their engines).
The ash particles are everywhere in various concentrations of density. As you fly through, the engines will keep on ingesting them like vacuum-cleaners.
When you have shallow ground fog over an airport, you can also see the runway quite clearly while looking down from above. But as you descend to a lower altitude into the fog, you won't see a thing ahead. It's the same principle.
so just fly under or around it - so what if it costs more gas/reduced payload..jets dont have to fly at 35000'!!
As long as you can get over the hills etc what is wrong with flying at low level ie sub 20k ... oh ....thats right too much fuel.
Well, you're obviously not a pilot.
If you chose a less agressive tone, you'd be more likely to get an explanation.