This report summarises the activities in the project Luftoperativ värdering och utveckling (Air Power Assessment and Development) during the period 2020-2022. The Swedish Armed Forces has given FOI the task to develop competence, methods and tools for comprehensive assessment of new air power concepts on an operational level. The purpose of the method is to provide better understanding of the effects and consequences of major changes to the air defence system. The work during this period has focused on continued development of the previously created assessment method, especially the use of wargaming as a supporting tool. Another aspect that has been studied is how cooperative engagement, involving complex systemsof- systems, can be handled in assessments. The method has also been tested, applying it to a number of test cases, providing experience for further development.