I think there will be drastically reduced capacity, but there will be international travel. But I'm sensing most think about international travel as "leisure travel" for holidays, but there is business traffic and VFR traffic as well.
Business traffic, it's difficult to see how that will or could progress, if 14 day quarantines remain in place at both ends.
I think then the main source of traffic is for non time-sensitive VFR (visiting friends and relatives) travel. There are a lot of people working or studying in different countries to their extended family, which have a different motivation to travel. For this group a week on a coast somewhere, is no substitute for a trip to visit loved ones, whereas it could be for overseas holiday.
In general, what happens to the quarantine conditions will drive the short-medium term traffic. Some people are not that time sensitive so may be able to cope with 14 days of isolation at either end of travel. But it will depend on cost. 14 days x 2 "self isolation" ... probably manageable. 14 days isolation at government expense x 2 ... manageable (less ideal) but unlikely this will continue... 14 days x2 @ own expense in government facility? Not really going to be attractive.