Flight cancellations due to strong crosswinds at Sydney Airport have caused travel disruption nationwide for a second consecutive day at peak school holiday time.
The airport chaos affecting thousands of travellers struck as a flight from Honolulu hit "severe turbulence" that injured some passengers.
At Sydney Airport, 18 flights were cancelled and dozens more were delayed by Saturday afternoon due to wind gusts of up to 45km/h and staffing issues.
More than 100 flights were cancelled on Friday, with the disruption spreading to airports across the country as thousands scrambled to find new flights on the first day of NSW's school holidays.
"Airlines are working hard to re-accommodate passengers and get them on their way," an airport statement said
Virgin Australia said more disruptions were expected.
"Multiple Air Traffic Control shortages occurring across the network over the last two days as well as a reduction to one runway in Sydney yesterday has caused a number of crew displacements and operational issues that are now impacting flights in Sydney, Melbourne and Brisbane," a spokesperson told AAP.
"More disruptions are expected due to the ongoing impact of the industry-wide disruptions over the last two days."
Sydney Airport traffic controller Airservices Australia said both airport runways were operational on Saturday and there had been "no shortage of air traffic controllers in Sydney".
"Any delays today at Sydney Airport are likely to be because of airline scheduling and resourcing," a spokesman told AAP.
One woman said her flight had been cancelled and a replacement flight would cost more than $1000.
She said she was due back at work on Thursday and wondered if it was worth travelling at all.
"It feels like it's hardly worthwhile ... I've got hire car and resorts and trips booked," she told Ten News.
Rebecca Louise Milburn said Sydney Airport was full of stranded children and elderly people after flights were cancelled on Friday night.
"Around midnight the plane had only just landed in Sydney and we got told it was cancelled," she said.
Flight Centre Australia managing director Graham Turner told Nine’s Today program the delays and cancellations would probably continue for the next six months due to staff shortages.
“It’s a problem not only with air traffic controllers - you know, the airlines have a shortage of pilots,” he said.
Jo Bradley said her flight from Sydney to Melbourne was delayed on Friday because of the shortage.
"All flights delayed due to the wind and the airport PA just announced that one of the scheduled flights to Melbourne 'doesnt have a pilot' right now," she tweeted.
On Friday evening a Hawaiian Airlines flight encountered turbulence that injured some passengers while flying over the Pacific Ocean, the airline said.
Flight HA451 hit strong winds and “unexpected severe turbulence” about five hours after leaving Hawaii.
"Four passengers and three flight attendants were initially treated by a doctor onboard and our crew members in consultation with physicians on the ground," Hawaiian Airlines said in a statement.
The Airbus A330 aircraft carrying 163 passengers and 12 crew landed "without incident" at Sydney Airport at 7.47pm on Friday, the airline said.
“We conducted a thorough inspection of the aircraft before boarding HA452, which departed Sydney to Honolulu at approximately 10.30pm local time yesterday.”
NSW Ambulance paramedics assessed 12 patients at the scene while three were taken to hospital with injuries including back pain.
Two passengers were taken to St George Hospital and another was transferred to Royal Prince Alfred Hospital, a NSW Ambulance spokesperson told AAP.
