In 1982, British Airways and Singapore Airways jumbo jets lost all their engines when they flew into an ash cloud over Indonesia. Reports said that the ash sandblasted the windscreen and clogged the engines, which only restarted when enough of the molten ash solidified and broke off. When the plane emerged from the cloud, the pilot repeatedly tried and failed to restart the engines. They were going down and down, and had just about accepted that they would have to ditch. But, at the last minute, one engine started. By repeatedly turning the engine over and having a clean airflow going through, the pilot managed to blow the ash out. Scary stuff and not something you want to take risks with. I heard on the news this morning that one of the airlines did a practice run last night, I'm guessing with a skeleton (and very brave) crew, but also with the company CEO on board as a sign of belief in the safety of their planes and reassurance to the public. Guess they don't get paid the big bucks for nothing!
Hoping for clear and safe skies again soon. Happy travels.