There is disagreement about whether Europe has adopted the best available strategy for dealing with atmospheric volcanic ash.
The split arises when individual airline leaders highlight an apparent failure by the authorities to allow business as usual when it looks as if it might have been possible. Meanwhile, the majority seem to believe the current strategy is the best available until we learn more about the phenomenon and gain more local experience of living with it.
Those who, like Ryanair's Michael O'Leary, say Europe should adopt Alaskan Airways' standard operating procedures conveniently forget a simple fact: Alaskan has lived with volcanic activity all its operating life. Alaska and the Rockies are its backyard, so it knows about the peculiarities and micro-climates. Its crews are trained and regularly refreshed in ash encounter drills. Its standard operating procedures were developed over years and are in the blood of its employees.
None of those things is true of Europe, which is at a very early stage on its ash operations learning curve. That does not mean we should fail to learn from best practice elsewhere, but it does mean that meteorologists and engine makers in particular should be doing more to improve knowledge of ash measurement techniques, operational risks and equipment limitations.
The Association of European Airlines has said it is pleased with the advances Europe has made in atmospheric ash operational strategy since last year. But that progress has been easy because the continent's 2010 encounter was marked by total chaos resulting from ignorance and unpreparedness.
This year we know more, but our knowledge is pathetic compared with what we need to know. Europe's volcanic ash risk management system is bound to err on the side of caution until our knowledge and experience increases, and with it our confidence.
Meanwhile, Iceland's volcanologists have warned us that their geologically young and vigorous island is entering a period of heightened seismic activity, so increasing our knowledge about all the parameters that define safe ash operation is not just an option: it is essential to do so if we are to avoid serious long-term economic damage.