Thakis
In the EU most of the aviation market is international (between different EU nations). The travel and covid restrictions imposed by different EU nations on one another (and also the uncertainty, as these measures seem to change every 2 weeks) mean that it's much more difficult for the EU airlines to get back to normal levels, customers don't know what to expect and don't want to have to quarantine when arriving/returning from holidays.
In the US however, there is a significant internal market: plenty of routes for the airlines to operate and the customers to travel on all while staying within the same country, and avoiding most/all covid restrictions.