Skeptics, consult post no. 308 by Lobo Tx
Lobo is a geologist. He explains how different volcanos make different particle contributions to various flight levels. So dodging Mt. St. Helens back in the l980s is far far different from ingesting abrasion downstream from Iceland.
Can't argue with a volcano. As it seems possible air travel may have to downsize, suggest, LoboTX, that you book your family holiday this summer to the UK via Cunard......
Meanwhile, those addicted to flying might enjoy visiting a local gliding club (consult British Gliding Association website); happy to get you airborne via winch launch, no flameouts guaranteed.
I still recall with pleasure sharing the airways with the jet traffic over Aboyne at 20,000' - in a glider. And enjoying a cross country flight in the UK of more than 500k. You really don't need any engine at all, chaps.
Now if we could only figure out a way to cut the noise and pollution from road traffic as well......