The biggest airline in Australia, Qantas, has pushed back its target to resume international flights to October.
The airline grounded its international fleet last March, and had hoped to resume flights from July.
Chief Executive, Alan Joyce, said they will now wait until the expected completion of Australia's vaccine rollout in October, with the exception of flights to New Zealand.
"Since the start of the year we have seen a huge surge of COVID cases around the world, new strains emerging and a shift from herd immunity as the threshold for opening to fully vaccination to be the threshold for opening the border."
Australia began its inoculation drive on Sunday, having reported just under 29,000 COVID-19 infections and 909 deaths since last March.
Qantas has said it will require international travellers to be vaccinated in order to board its flights.
The airline is not expecting international travel numbers to return to their pre-COVID levels until 2024, with capacity expected to be at 40% next year.
Qantas usually earns the bulk of its profit from the domestic market.
But Australia's state border closures have hampered that.
In the six months to December, the airline's revenues fell by 75% to 1.9 billion dollars.