My flight was cancelled/rescheduled as well. Pretend you are Delta and schedule a bunch of nonstops from all your hubs to all of the major cities in Europe and then oopsie, turns out not that many Americans want to go to Europe right now and no Europeans are allowed in to the US. But- there are a lot of Americans who want to go to DisneyWorld and other Florida beaches, Cancun, etc. What to do? Consolidate your nonstops to just a few of your hubs, reroute everyone there, maybe change up a bit which European cities you are going to fly into, and then put all those big transatlantic planes into service from your hubs to Orlando and send the folks to see Mickey instead. Instead of Atlanta to Madrid nonstop both ways, I am still on a nonstop from Atlanta to Madrid but the way home goes JFK and then to Atlanta. And the plane from JFK to Atlanta is larger than the one from Madrid to JFK. Interestingly, all three of those flights have just about 100 people on each of them. There are 120-220 seats available on those flights right now, which suggests there might be some further consolidations before September gets here. I'd just roll with it.