There is a new phrase rattling round: it is "travel bubble".
The premiers of Tasmania, South Australia and the ACT have been talking to each other about creating a zone in which easy, quarantine-free travel is possible.
"We've all agreed the project is a priority," ACT Chief Minister Andrew Barr said. He thought it could happen as early as July.
On top of that, there might even be a "trans-Tasman travel bubble", with unrestricted travel between Australia and New Zealand. Prime Minister Scott Morrison has indicated he is working towards it.
We need to know what it means and how we might fit into it.
What is a travel bubble?
Let's start with a formal and general definition: "Travel bubbles, also called travel bridges or corona corridors, do away with that waiting period for a select group of travellers from certain countries where the coronavirus has been contained," according to the authoritative Smithsonian Magazine.
In a travel bubble, a group of countries or areas (like states) within a country agree to open their borders to each other while keeping those borders closed to other countries or states.
In other words, there's easy, quarantine-free movement within the bubble but the bubble is closed to outsiders who might bring in the virus.
What conditions are necessary for a travel bubble to work?
The first and obvious condition is that all areas within the bubble need to have zero or near zero cases of COVID-19, with the certainty that any new cases can be closed down quickly by isolating the patient and tracing all his or her contacts.
New Zealand is not far from that situation. On the latest information, there was just one case there and once that person recovers, and if no new cases emerge, the virus would seem to be beaten.
That is true, too, of the ACT - but it is not true of other parts of Australia.
A second condition for a trans-Tasman bubble would be that people from areas which still have cases could not get to Canberra and transit onwards to New Zealand. Canberra and Wellington are "clean" of the virus but transit remains an issue.
All the territories within the bubble have to trust each other. They have to be sure that the other country really is COVID-free.
What are the hurdles?
Conditions need to be similar in all territories within the bubble.
At the moment, for example, visitors to South Australia and Tasmania have to go into 14 days quarantine. The ACT's argument is that Canberra is infection-free so Canberrans don't present a risk.
But some form of exemption from quarantine for Canberran in-comers to South Australia and Tasmania would need to operate for the bubble to work.
This would have to include New South Wales and Victoria because travel between these two states and the ACT is already unimpeded.
Tourist agencies generally do not see quarantine as the way forward because short-term tourists wouldn't accept quarantine. Travel with quarantine wouldn't open up the economy very much.
What are the benefits?
The obvious gain is that people like freedom of movement.
Canberrans like to go to the South Coast of New South Wales to relax. People in Victoria, New South Wales and other states and territories as well as New Zealand might want to come to Canberra to see the sights.
But there is an economic benefit which helps even those who don't want to travel.
The more we can get business moving again, the less the rate of unemployment will rise as the world economy slows (or even crashes).
Tourism is New Zealand's biggest earner of foreign currency and 40 per cent of the people who visit New Zealand come from Australia.
In normal times, about 1.5 million Kiwis visit Australia each year and leave about $2.7 billion dollars in Australian bank accounts through their spending. Without travel across the Tasman, that's much-needed money which doesn't get spent in Australia.
Might other countries be included?
We are at an early stage. There isn't even a travel bubble within Australia yet - but countries all over the world are looking at how Australia and New Zealand might proceed.
The three Baltic countries, Lithuania, Latvia and Estonia, have established a travel bubble but they are small, very closely integrated and not open to large influxes of tourists.
The chief executive of New Zealand's tourism organisation, Chris Roberts, said that "if New Zealand and Australia can show this can work, then it is likely to be adopted elsewhere". The alternative was waiting for a vaccine and that might take a year to 18 months - if ever.
If the bubble works in our part of the world, we might look to extend it to other countries which have contained the virus, including Taiwan, Hong Kong and South Korea. Expansion would have to be mutual. Some of the Pacific Islands, for example, have been virus-free but they would need convincing that Australians should be allowed in while the virus remained in Australia.
Is there a middle way?
Some countries are deciding that the choice isn't a straight one between the complete closure of borders and the opening of them. It's a matter of balancing risks.
As testing becomes better, it may be possible to test passengers on departure and arrival. China and South Korea have agreed to ease quarantine for some business travellers in what's called a "fast-track" system.
The two countries have got the number of cases right down. They want to get trade moving again so South Korean business people can travel to ten economically important Chinese regions after going through "minimized" health screening and quarantine measures.
The two countries have been talking to Japan with a view to including it in the limited travel bubble.
In the absence of a vaccine, the way forward is likely to be step-by-step, with virus-free islands (like Australia and New Zealand) opening travel between each other.
It's not easy - but it's progress.