The airport has been publicly at loggerheads with Qantas for months, repeatedly speaking out against the high cancellation rates plaguing flights between Sydney and Canberra.

Canberra Airport has gone as far as seeking federal government intervention and recently met Deputy Prime Minister Michael McCormack to discuss the issue.

Qantas Domestic boss Andrew David has now hit back.

“We deal with airports around Australia and around the world, and none of them behave the way Canberra Airport does. It’s bizarre,” Mr David said.

“It’s hard to see how a company can think that attacking its biggest customer, which Qantas is, will improve matters.”

Canberra Airport managing director Stephen Byron said it was crucial the two companies had a constructive relationship, but also important to prioritise customers.

“We want to stand up for our Canberra customers and those flying here, so they get a good quality of service,” he said.

“When we’ve had very high and concerning cancellation rates by Qantas - that are three to four times the national average - we seek a better deal and a more reliable service for our customers.”

Although the stoush over flight cancellation rates has played out in public in recent months, it is understood Qantas has been dissatisfied with the airport for some time.

These tensions boiled over in March last year when a Qantas 737 flying to Sydney made an unscheduled landing in Canberra due to bad weather.

Qantas bristled when Canberra Airport parked an escort car behind the plane and asked for $18,000 in diversion charges before the plane, carrying almost 170 passengers, could take off again.

It is understood Canberra Airport initially wanted the $18,000 charge paid immediately by credit card, although the fee was later reduced.

Mr Byron said the diversion charge was a disincentive for planes to make unplanned landings at Canberra Airport without having a formal agreement in place.

These agreements were necessary as a safety measure because Canberra Airport only had a limited number of spots to accommodate international diversions, Mr Byron said.

Qantas previously had such an agreement with Canberra Airport, although this had lapsed prior to the unscheduled landing in March.

A senior Qantas spokesman said decisions on where to divert were made for safety, not commercial considerations.

“Diversions are, by their very nature, unexpected,” the spokesman said.

“Cost aside, this episode involved Canberra Airport essentially ransoming an aircraft full of passengers on the tarmac by parking a car behind it. This behaviour beggars belief.”

Qantas has previously described how a combination of engineering issues and pilot shortages contributed to a spike in cancellations in late 2017.

"The cancellation rate on Sydney to Canberra is higher than the national average, and we're working to fix that, but it's still very low in the scheme of things," Mr David said in April.

"It's also one of the highest frequency routes in the country, so if a flight is cancelled for operational reasons, then the wait time is minimal."

Instead of working to address the issues in a constructive manner, Qantas said Canberra Airport had tried to shame it into action.

“Cancelling or delaying flights disturbs passengers and costs us money, so we have plenty of reasons to minimise them,” Mr David said.

“Canberra Airport seems to think it’s some sort of conspiracy and that they can publicly shame us out of it. That’s simply not how it works.”

In early April Mr Byron wrote to Qantas and Virgin Australia, offering $100,000 to the airline with the lowest monthly cancellation rate on the capital to Sydney route.

Neither airline accepted the proposal, although Mr Byron said flight reliability had improved in the wake of the offer.

Steps by Qantas to address cancellations had resulted in improvements, which Mr Byron acknowledged.

“We are positive about the response and we are respectful of that,” he said.

The latest figures for the Canberra to Sydney route showed 2.9 per cent of flights were cancelled in March.

This showed an improvement of 5.2 percentage points since the route topped the nation for cancellations at 8.1 per cent last September.