Eyjafjallajokull is still there, temporarily dormant. So is its more powerful neighbour Katla. So the ash will be back.
Surely, Europe has a plan this time? Well yes and no. Mainly no.
A plan exists, but individual states have not signed up to it, so nobody really knows what will happen. There may be up to 27 different reactions, with each state looking shiftily at what its neighbour is doing before deciding whether to do the same or break ranks. Meanwhile the ash will drift with the wind, contemptuous of borders and politics.
A bit like the last time, then?
CANSO (the Civil Air Navigation Services Organisation) held an open discussion about Europe's ash performance last time (late April/early May) at its recent Oslo AGM. I was moderating it, so let's look first at what aviation leaders said about what happened then, and finally we'll look at what may happen next time.
First, Doug Johnson of the London Volcanic Ash Advisory Centre (VAAC) set the scene by summarising the centre's capabilities for ash cloud monitoring and modelling.
Doug Johnson, London VAAC
He revealed that the London VAAC's ash cloud detection, tracking and modelling system had proved accurate when compared with all other global capabilities. In a future event the VAAC would be able to provide daily actual and predictive charts based on the new ash concentration zoning system thrashed out during the recent crisis.
Eurocontrol director general David McMillan was tasked with assessing whether the decisions to close much of Europe's airspace were justified.
David McMillan, Eurocontrol DG
He began by attacking those who said that the grounding was a fuss about nothing, and suggested the picture behind him of ash powering into the upper atmosphere indicates it had millions of tonnes of substance.
McMillan argued that the lack of ash-tolerance data for engines and airframes available to ATM providers and airlines gave the aviation authorities no choice but to recommend grounding until the ash dispersed or safe levels were scientifically identified.
From the floor, the Irish Aviation Authority's chief executive Eamonn Brennan also noted the total lack of response from EASA, suggesting the agency's leadership would be a key factor in a future coordinated response. Ireland, the UK and Iceland suffered more ash contamination than any of Europe's other flight information regions.
IATA's Jeff Poole accused European agencies and governments of "staggering complacency" when the ash cloud arrived, with no response available during the first weekend of the event.
Jeff Poole, IATA
He voiced the hope that the huge losses to the European economy caused by the grounding may wake politicians up to the importance of aviation and and the need to provide its essential infrastructure.
Ásgeir Pálsson, head of Icelandic ATM provider Isavia called for validation of the parameters for ash-damage tolerance to airframes and engines.
Ásgeir Pálsson, Isavia
Pálsson also fired a shot at airline claims by suggesting that "random test flights achieve nothing".
Dieter Kaden of German ATM provider DFS pointed out that engine manufacturers were still not providing the support and data that might be expected, and that warranties and insurance for engines were still being removed by manufacturers from aircraft flying close to ash.
UK NATS CEO Richard Deakin suggested that the ash cloud modelling had proven to be pretty accurate, although he would have liked to have seen more data derived from sampling. He also wants to see a European regulatory approach agreed, to avoid the 27 totally uncoordinated national responses.
Finally, Dan Smiley (FAA and CANSO) summarised the
This sets out a detailed, coordinated response to a volcanic event. His presentation made it clear that the difference from Europe is that there is a single plan, while neither Europe as a whole nor any of its 27 member states had any plans at the time that Eyjafjallajokull erupted. The Alaska VAAC disseminates the ash data rapidly to all parties, the FAA follows up with advice to avoid ash at all times, but airlines are allowed to make their own decisions in the end.
What Smiley didn't add is that the airlines usually take the advice to avoid the ash, and the amount of affected traffic is minuscule compared with Europe.
So what has Europe agreed to do next time?
It has set up an Aviation Crisis Coordination Centre co-chaired by the European Commission and Eurocontrol. The only trouble is that the ACCC has been given no executive power, so none of the states or air navigation service providers has to take any notice of what it says. They might choose to do so, but who knows until it happens?