Sydney: Australian flights grounded by the Chilean ash cloud resumed on Wednesday as the plume cleared, but thousands of passengers endured lengthy delays as airlines scrambled to clear a huge backlog.
Hundreds of services were cancelled Tuesday in Sydney, Melbourne, Adelaide and Canberra but the threat of prolonged disruption eased as the ash from the Puyehue volcano eruption pushed out towards the Tasman Sea and New Zealand.
"The ash cloud affecting eastern Australia has cleared, and airlines are returning to normal operations Wednesday afternoon," said the Bureau of Meteorology.
But while mainland routes got back in the air, Qantas, Jetstar, and Virgin services to Tasmania and New Zealand were all halted until further notice as the ash moved south.
Qantas restored flights to and from the South Australian capital Adelaide before dawn, followed by Melbourne.
Canberra and Sydney routes were operating again by early afternoon, including international flights, although Qantas said delays were expected on overseas services into both Sydney and Melbourne.
Virgin also resumed flights from the major cities.
Despite planes being airborne, Qantas spokeswoman Olivia Wirth said thousands of customers had been affected once again.
"There were a significant number of people delayed over the past 24 hours. There were around 20,000 yesterday and we expect that number to go to around 50,000 today," she told Sky News.
The airline was putting on extra flights to work through the backlog of passengers, some of whom have been stranded for two days.
"The backlog will take a significant time to clear but we will be looking at putting on as many extra flights as we can," said Wirth. "Fingers crossed, we won`t be seeing this again."
Despite other airlines taking a conservative approach, Air New Zealand has maintained most services by flying under the plume, and said its routes continued to operate as normal.
New Zealand Civil Aviation Authority meteorological manager Peter Lechner said the cloud was expected to cover the entire country later Wednesday and due to slow-moving winds would linger for "at least a day or two".
"It will be at a height of 20,000 feet (6,000 metres), which provides plenty of scope to fly under the cloud," he added.
Ash poses a significant threat to aircraft because once sucked into engines it can be transformed into molten glass by the high temperatures and potentially cause an engine to fail.
The cloud first entered Australian and New Zealand airspace over a week ago, causing some airlines to ground all flights to affected areas while others chose to divert under and around the plume.
Australian Transport Minister Anthony Albanese admitted the flight chaos would come at a cost.
"There`s no doubt there will be a significant cost to all the airlines, but also an economic cost (to the country as a whole) -- people are not flying into Australia," he said.
"This means lower revenues for the tourism industry."
Australia`s Tourism and Transport Forum put the impact on the tourism sector at over Aus$10 million (US$10.6 million) a day, while Qantas said disruptions due to the ash had cost it Aus$21 million even before this week`s cancellations.
Qantas chief executive Alan Joyce emphatically denied that the airline had been too cautious in grounding flights.
"It`s absolutely worth it. I would spend anything to ensure the safety of every single one of our passengers," he said.