Australian air travellers have been warned to expect more disruptions over the next 12 months, as the industry scrambles to fill critical worker shortages ahead of the July school holidays.

It's been a torrid few months for passengers, who have faced delays, cancellations and missing luggage over the recent Easter break and the Queen's Birthday long weekend.

Employers are rushing to fill 5,000 job vacancies around the Sydney Airport precinct, which shed 15,000 jobs during the border shutdown.

Chief executive of Sydney Airport Geoff Culbert told 7.30 airports would continue to struggle to recruit enough workers in time for peak periods.

"I'm not going to sugar-coat it," Mr Culbert said.

"It's going to be challenging. We're still going to have staff shortages in the June-July school holidays. We're throwing everything we possibly can at it.

"I think you're going to see airports struggling for staffing and recruitment for the next 12 months."

Sydney Airport is urging domestic travellers to arrive two hours before their flight, and international travellers to arrive three hours ahead, to allow for delays.

Across the world, airports are struggling to deal with the resurgence of travellers.

'Not up to scratch': Customers blast airlines on social media

Customers have vented their frustrations with Australian airlines on social media, complaining of flight delays, cancellations, missing baggage, hours-long queues at airports, inability to reach call centre staff, and accusations of unfair terms and conditions on flight credits. 

ABC's 7.30 has spoken to Qantas and Virgin passengers, whose luggage has been missing since April. 

"I followed up with Virgin multiple times and was just told the same story: 'The bag's coming' … but it just never came," traveller Clinton Press said.

Mr Press said he was unsatisfied with the amount Virgin had offered in compensation. 

Virgin declined to be interviewed but said it was working around the clock to help their customers.

Long-time Qantas customer Kevin Burke travelled from Darwin to London on a series of connecting flights.

He told ABC's 7.30 the trip was plagued with problems.

"I think Qantas' brand is very, very tarnished. The service is not up to scratch," he said.

"When we arrived at Heathrow, the pilot told us that the entire plane's luggage had been left in Australia to make room for fuel."

Mr Burke's luggage arrived three days later.

Passengers sleep in airport after cancelled flight

Last Thursday, a Qantas flight from Dallas to Sydney was cancelled at 2am, due to an engineering issue, leaving many to sleep on the airport's floor, including some of the Gaudin family. 

"No one was telling us what was going on," traveller Kat Gaudin said. 

"When the [kids] woke up, they were cranky, hungry, a little bit confused." 

The mother of four said she felt "let down" by the national carrier. 

Qantas has apologised for the inconvenience caused to passengers on the flight. 

The company's chief executive, Alan Joyce, has shifted his language after he faced a customer backlash over his comments that passengers were not "match fit" over Easter, conceding the industry was "rusty" as it got back up and running.

Mr Joyce declined to speak to ABC's 7.30, but told reporters in Doha on Sunday night, "there are blocks in the chain all the way through".

In a statement, Qantas said it was "working hard to fix the problems we have" and has apologised to customers who have had their baggage delayed. 

"We've got a lot of confidence leading in to the school holidays [that] we'll see a different outcome."

Sacked Qantas workers find jobs but say they're worse off in survey

The Transport Workers' Union argues Qantas's outsourcing of workers in 2020 has led to the current problems.

"This is about a fundamental structural problem within aviation that has been deliberately created by Qantas over the course of the Joyce administration," TWU national secretary Michael Kaine said. 

The Federal Court later found the sackings were illegal and the airline now plans to appeal to the High Court.

A TWU survey of 1,100 former Qantas workers outsourced in 2020 found that, while the majority have found new jobs, 70 per cent say they are worse off.

And 71 per cent say they have experienced financial hardship, while 30 per cent have developed depression or anxiety.

Qantas denies the union's claims on outsourcing.

Watch this story on 7.30 on ABC iview.