I don't know for sure about global, but the Eurocontrol forecast for Europe until March says that, with the current state of affairs, traffic numbers will stay at about 40-50% of 2019 levels for the coming 6 months. Obviously, this can be reviewed in either direction at any time. The next EC meeting on border reopening is on 13 October, if memory serves me well. Obviously, the EC is advising in favour of a more unified approach than now that could aid travel recovery, but it remains to be seen how willing to take part the national governments will be.
If you ask me, the optimistic scenario is some more significant movement towards spring 2021, hopefully followed by a summer that will be better than summer 2020. Whether that will be achieved through the natural course of the pandemic, through a vaccine, through cheap and easy testing or through a combination of those - we can only guess for now.