April's closure of European airspace, caused by clouds of volcanic ash, led to disruption for hundreds of thousands of travellers.
And for one of them, Denis Cairnes, it meant flying an extra 1,900 miles and waiting three weeks before returning to the UK from a holiday in the Philippines.
He was due to fly back via Hong Kong, after taking a fortnight's holiday in April to visit one of his sons on the island of Palawan.
At a stop-over in Cebu City in the Philippines on the way home, his airline Cathay Pacific told him that the last leg of his trip would leave as scheduled, despite the developing chaos in Europe.
But when he got to his Hong Kong hotel in the early hours of 20 April, expecting to fly to London the next day, things had changed.
A five-line message told him the journey had been cancelled, and the next available flight would be on 12 May - three weeks hence.
The last line of the message from Cathay Pacific, said, without any trace of irony: "Have a good evening!"
Three week delay
Mr Cairnes now had an obvious problem.
"I was faced with what on earth I did with three weeks. I didn't want to stay in Hong Kong on my own, which would have been extremely expensive," he says.
"I went to see Cathay Pacific but they couldn't make any change to the flight dates, nor would they help with any flights back to the Philippines."
He decided to rejoin his son in the Philippines and sit out the wait, until making the return journey to Hong Kong again, for his eventual return home on 12 May.
An enforced additional holiday does not sound too much of a hardship, but that extra trip from Hong Kong to Palawan via Manila - and back - was a distance of nearly 1,900 miles.
It cost him an extra £550 in plane tickets and accommodation bills, as well as the inconvenience of a prolonged period away from home.
"I missed the election and I missed the funeral of one of my oldest friends in the UK and various other appointments," says Mr Cairnes.
"It was certainly expensive because I had to pay for the flights back to Palawan and then back again to Hong Kong, plus another night at a hotel in Hong Kong, and three nights in a hotel in Palawan when my son wasn't there."
Things would have been even worse if he had not had the money, or a base to return to, albeit far away.
"Had I not actually had the funds to do it, and the time, I would have been really stuffed," he points out.
"I would have been stuck in Hong Kong with no money, with three weeks to wait."
Many of those who had their flights cancelled did not wait for airlines to return them home and sought alternatives. So why did Mr Cairnes not try to get home a bit quicker, via some other route?
"I did contemplate the idea of flying, perhaps to Rome, and catching a train back to the UK, but even that was a bit uncertain and seemed to change daily," he explains.
"We didn't really know what the chances were of getting anywhere like that, and of course everybody was trying to do it so there was an awful scramble to get on some of those flights.
"You would have to have been willing to fly to any one of a number of different destinations, from which you may or may not have been able to get on."
The thing that sticks most in his mind is that he was simply left to his own devices, with no help.
"At every Cathay Pacific office I went to there were mobs of people waiting and trying to get some sense out of them, trying to reschedule flights," he says.
"The manager of the Cebu office eventually appeared to address the mob and said she was very sorry about the problems and they were trying to reorganise people's flights, but beyond that, there was no suggestion of any help at all."
The situation in Hong Kong was worse.
"There was even less help, and communicating with them was extremely difficult because they didn't answer the phone," Denis explains.
"I went to their office in Hong Kong and they said they couldn't do anything at that stage, they didn't seem to be at all organised."
Cathay Pacific told him he would not be given any form of compensation.
European rules say airlines should have paid for his hotel and food - but this would only have applied had he been stranded within the EU or had been travelling on an EU airline.
At his home in Mortlake in south west London, Denis is still finding it hard to get much satisfaction.
"I haven't been able to speak to the travel insurance people, they have only recorded announcements [on the phone] saying I should take up the matter with the airlines first," he explains.
"I phoned the Cathay Pacific offices and was kept on hold for about 45 minutes and gave up in the end," he adds.
On being told about Denis's story, a spokeswoman for Cathay Pacific acknowledged that some of its stranded passengers had hoped for more help, and said the airline would now contact him directly.
But she pointed out that the disruption had been unprecedented and on a vast scale, with 93 of its flights cancelled and 20,000 passengers stranded.
"Given the fluidity of the situation at the time, our front-line staff had done all they could under very difficult circumstances to help the stranded passengers," she said.
"The huge backlog of passengers and other constraints, such as the insufficient landing slots and airspace congestion in European airports, had prevented us from bringing home all our stranded passengers as quickly as we wanted.
"While we did receive a lot of compliments from other passengers for the way we handled the disruption, we know that there are cases where our passengers thought we could have done better," she added.