Qatar Airways has postponed its flights to and from Canberra in a set back for the airport's attempt to get back on the international map.
The first flight was due on Sunday but the airline has blamed "operational reasons" for postponing it.
Canberra Airport said the glitch was merely a delay and not the prestigious Middle Eastern carrier pulling out.
Canberra Airport executives have also been negotiating with Singapore Airlines to try to persuade it to return but so far to no avail.
On the Qatar postponement, Canberra Airport's head of aviation, Michael Thompson, said: "The delay of the once-daily service from Doha to Canberra via Melbourne is unfortunate, but we look forward to their return on 1 December and the restart of international services to Canberra."
Sunday's arrival of the first international flight since they were cancelled during the pandemic would have been a red-letter day for Canberra Airport.
When the resumption of the service was announced in July, airport chief executive Stephen Byron called it a "tremendous vote of confidence".
"This is a great first step and I think it's going to put the pressure on everyone else to start ramping up their international flights to Canberra."
The airport was still "pushing very hard" for Singapore Airlines to resume flights, he said two months ago.
"We'd love to see Singapore Airlines back here before Christmas, the reality is it might be something like March next year."
ACT Chief Minister Andrew Barr said at the time: "It's great news for Canberrans wanting to travel overseas, particularly to Europe, the United Kingdom and the Middle East and it's a huge boost to our local tourism industry."
The Qatar service would mean that passengers could board in Canberra and fly to Doha, one of the big hubs between European cities and Australia, without transferring from the domestic terminal to the international terminal and re-checking in in Sydney. Luggage will go straight through to the final destination.
On the return journey, passengers would have gone through customs and immigration in Canberra.
Apart from convenience for Canberrans, the return of Qatar Airways is a relief for the airport owners because it puts Canberra back on the international flight map.
