Cancellations on flights between Canberra and Sydney remained three times worse than industry standards in October, leading to renewed calls for intervention from the federal government.
Canberra Airport boss Stephen Byron said passengers flying to and from the capital were being "slugged" by major airlines and called for the federal government to establish an industry taskforce.
Department of Infrastructure and Regional Development statistics showed flights between Canberra and Sydney topped the nation for cancellations in September, at 8.1 per cent - far higher than the national long-term cancellation rate of 1.4 per cent.
October data published this week showed Qantas cancelled 8.8 per cent of its flights from Canberra to Sydney, affecting as many as 6000 people travelling on the route.
Virgin Australia cancelled 2 per cent of its flights in the period, while the overall cancellation rate was 6.6 per cent.
Between Sydney and Canberra, 5.9 per cent of flights were cancelled in October, 7.7 per cent by Qantas subsidiary Qantas Link and 2 per cent by Virgin.
Nationally cancellations were highest on the Mount Isa to Brisbane route at 10.7 per cent in the month.
The average cancellation rate around Australia in October was 2.3 per cent.
Qantas and Qantas Link cancelled 43 Canberra to Sydney flights in October, while Virgin Australia cancelled five flights.
In the other direction, Qantas and Qantas Link cancelled 38 and Virgin cancelled five.
Qantas Link had the highest percentage of cancellations nationally in October at 4.7 per cent, followed by Virgin Australia's regional airlines at 4 per cent and Regional Express and Qantas at 2 per cent.
Mr Byron said Canberrans paid premium prices for flights to and from the capital and they should be entitled to receive a reliable service.
"This issue has been around for a long time and just because these figures are twice as bad as normal isn't an excuse - normal is three times as bad as it should be," he said.
"Canberra is getting slugged with perpetually poor results on the Canberra-Sydney route in terms of cancellations.
"It's not like these are low cost airfares like on Ryanair or Easyjet, that one might expect a level of unreliability about them, these are not the sorts of tickets people have bought when they've purchased their airline tickets."
He has proposed a taskforce to include airport officials from Sydney and Canberra, as well as representatives from Qantas, Virgin and Airservices Australia.
"It is immensely disappointing to see effectively Canberra targeted or flights in and out of Canberra on our three main routes be doing devastatingly poor in result terms," Mr Byron said.
"The long term average is 1.4 per cent, the industry standard of what is acceptable is below 2 per cent and the reality is on the Canberra to Sydney route, it hasn't been below two per cent for more than five years."
Qantas Link chief operating officer Jenny Chamberlain said the higher cancellation and delay rates were disappointing and fell "well below the standards we set for ourselves and our customers."
"We've previously said we are taking active steps to improve overall reliability by making some adjustments to our network and schedule," she said.
"These plans are well under way. We've already seen a significant improvement in performance for November and expect the cancellation rates in impacted ports like Canberra to continue to improve from December onwards."
Qantas has adjusted some of its domestic flights to improve reliability into Canberra, using more 737s instead of smaller 717 aircraft and adding about 60 seats on every flight.
Its cancellations from Canberra are about 4 per cent this month, down from 7.2 per cent in October, while inbound flights are about 4.5 per cent, down from 6.7 per cent.