The arguments here seem to be based on either one of two polemics:
a) There is no problem. We've all been flying near volcanoes for years and only those aircraft unlucky enough to stray too close have ever had a problem. Or
b) You pilots are all crazy. There's no way anyone should be flying under any circumstances when there's all this volcanic debris in the air.
Patently both points of view are extreme and both are probably wrong. Yes, it's true that we've been flying for years around these things, but we haven't ever, as far as I know, had the current combination of this type of volcanic eruption and a static met situation which parks the lot over the world's busiest airspace. It's probably also true that we haven't previously been able to detect much of the stuff that's now keeping us on the ground, and that a good deal of engine wear in the past maybe down to expeosure to similar stuff.
It's rubbish both to suggest that any flight that gets airborne now will suffer a multiple flame-out and all on board will die, just as it's rubbish to say that there will be no ill-effects on any aircraft that does fly. What has to be determined is the acceptable potential maintenance load we may be incurring if we fly sensibly removed from the densest ash concentrations. It is obvious that all jet transport aircraft are exposed to some extent to volcanic ash every time they fly, as volcanoes are continuously erupting around the world and the residue is constantly present in the atmosphere. As data has not yet been adequately gathered to assess what effects this current phenomenon has on aircraft, it makes economic sense that that data is acquired right now. Whether anyone here likes it or not, there are aircraft and crews available and ready to do this if the funding is found. I have no doubt that, facing financial oblivion otherwise, the airline industry will find that money.
Indeed, it seems they are finding it, as KLM, Lufthansa and BA (and maybe others) are launching test flights as we write. However, are these tests co-ordinated and is the data that is acquired representative and readable across to the general industry? Let's hope so.
Not flying indefinately is not an alternative. Pragmatism must win out.