I see Aus/NZ having a solid plan for this as suggested above, as well as other island nations (minus UK). I can see the airlines accommodating this too (ie if your last minute test is positive we will move your flight two weeks forward) as they'll need the business. As well within Europe lightening up their border restrictions when things have calmed down in next few months.

I'm not sure about travel between Canada and USA, my guess is opened up by late summer but such a political hot topic hard to say, and with a huge land border there are no easy solutions. I'm guessing its just going to be symptom screen, quarantine wouldn't be feasible, and eradication is basically impossible in either country at this point.

easy to get pessimistic, but in the medium to longer term travel is too big to fail imho