In the ongoing series of comparative reports between Europe and the US, the most recent update looks at operational as well as economic air traffic management (ATM) performance. It reviews both ATM systems since the outbreak of the COVID-19 pandemic in 2020 and continues to track longer term trends and disparities identified in earlier reports. Although both regions are similar in terms of airspace size, variations exist in their regulatory framework, funding, operational structure, and the measures they employ for air traffic flow management (ATFM), which all have the potential to impact ATM performance. (....)