And if you take the risk and fly and it all goes horribly wrong then some people:
a: Will never fly again
and
b: SLF will avoid that company like the plague and it'll go bust.
Which is why we need more research and testing - now.
There should have been research aircraft up every day, measuring the concentrations and (supposed) turbine damage at these concentrations, so we have some real data to go on. (the Nimrod on two engines)
Sitting on the ground and saying 'we are all going to die' is going to do nothing for aviation. Remember, this eruption may go on for the next two or more years.
Do we dispand aviation completely, or do something????
.