Flyers continue to face big delays at airports around the country after the check-in system used by several airlines crashed, meaning passengers had to be checked in to their flights manually.
The glitch has now been fixed after the three-hour failure of the Navitaire check-in system, which is used by Jetstar, Virgin, Tiger, and REX.
Travellers continue to wait in long lines as flights have been delayed in Sydney, Melbourne, Brisbane and Perth.
Domestic and international flights have been affected but Jetstar could not say how many flights have been delayed.
Tiger Airways spokeswoman Vanessa Regan said the Navitaire system came back online just before midday (AEDT) on Saturday.
She said the outage had caused a half an hour delay for several Tiger flights.
"We did have a couple of minimal delays but we expect to smooth those over now," Ms Regan said.
Virgin Australia spokeswoman Melissa Thomson said check-in processes had returned to normal and the airline would work to minimise delays.
A Jetstar spokesman said the outage caused delays across the airline's network and staff were working to process delayed passengers as quickly as possible.
"We know that this has inconvenienced our customers and we thank them for their patience as we process passengers," the spokesman said.
A Navitaire system crash in 2010 caused chaos for Virgin Blue passengers nationwide, with two days of flight cancellations and delays, forcing some to put themselves up in hotels.
Virgin boss Richard Branson apologised, saying it had been a "terrible 24 hours".
The airline blamed Navitaire for the chaos and said it was considering legal action, but reached a confidential settlement in 2011.
Ms Thomson said Virgin was migrating to a new IT system next year and would no longer be using Navitaire.
Anna, who is flying from Melbourne to Maroochydoore, had to wait for over three hours for her flight.
"With a little two year old in tow it's not fun, but it's more the elderly people they should be catering for," she said.