Understaffed airports and airlines from Australia to Europe are struggling to cope with a fresh rush of travelers, with long queues and flight disruptions expected to persist as the busy Easter weekend approaches. 

Passengers checking in at Sydney Airport this week have waited for hours in queues snaking outside terminals. Staff absences are running as high as 50% at Qantas Airways Ltd., while the airport’s workforce is little more than half its normal size. The U.K. has also been hit by disruptions and flight cancellations.

The aviation industry axed hundreds of thousands of workers to get through the worst of the Covid-19 pandemic. That left airports and airlines short of staff to handle an upswing in travel as much of the world drops entry restrictions, while the virus continues to ripple through flight crews and ground workers. 

Sydney Airport, Australia’s international gateway, has called the combination of factors a “perfect storm.”

“We just can’t get staff,” Sydney Airport Chief Executive Officer Geoff Culbert said on Australian television Tuesday. “It’s going to be like this for a little while.”

Culbert said on some days the airport can find itself running at 60% staff capacity while having to process more than 80% of pre-Covid passenger volumes. “The maths leads you to where we are,” he said.

Ahead of the Easter holiday, there’s already nowhere to park at Sydney Airport for those taking a domestic flight.

The rebound in some major markets including the U.S. has caught airlines and airports on the hop. Smaller markets such as Thailand and Singapore that are yet to reopen to the same degree aren’t seeing the same delays.

U.S. airports are “chock-a-block” with travelers, AirAsia Group Bhd founder Tony Fernandes said in an interview from New York with Bloomberg Television on Tuesday. He said a similar recovery in air travel in Asia, where restrictions in places such as China remain, was still a few months away. 

U.K. holidaymakers face lengthy queues this week. Almost 4.2 million travelers passed through London’s Heathrow Airport in March, a more than sevenfold jump from a year earlier. Border Force staff from Scotland and Northern Ireland are being deployed to help mitigate queues at the airport, which is racing to hire 12,000 new workers after the U.K. lifted curbs on travel.

Low-cost carrier EasyJet Plc and British Airways Plc both canceled flights Sunday. On the same day, one-third of EasyJet services were delayed, according to the tracking site FlightAware.

JetBlue Airways Corp. is planning to reduce its summer schedule to avoid flight disruptions due to staff shortages, CNBC reported Sunday. The U.S. airline is offering flight attendants $1,000 bonuses if they don’t miss work from Friday through the end of May, CNBC said.

Qantas has asked unrostered pilots to join three international flights and several domestic services on Wednesday that are critically short of crew, the Sydney Morning Herald reported, citing an internal note from the airline.

Qantas CEO Alan Joyce said Monday that staff absences were running at between 20% and 50% due to Covid infections or isolation requirements.

He said delays were exacerbated because passengers have forgotten what they need to do when they fly. 

Sydney Airport security is rescreening 30% of travelers because they’re forgetting to remove items like laptops and aerosols from their bags, Joyce said. Before the pandemic the figure was 10%, he said.

“We’re all rusty,” Joyce said.