Integration Between 4th and 5th Gen Aircraft Among The Key Themes Of Astral Knight 2021 Exercise Integration Between 4th and 5th Gen Aircraft Among The Key Themes Of Astral Knight 2021 Exercise Some images of the assets taking part in Astral Knight 2021. (All images: Claudio Tramontin) Astral Knight 2021 was a U.S. Air Forces in Europe-Air Forces Africa-led joint multinational exercise that took place in the Adriatic region. From May 13 to 21, personnel and assets from the U.S., Albania, Croatia, Greece, Italy and Slovenia, took part in the latest iteration of Astral Knight, a joint multinational exercise with the “aims to enhance the command and control integration, coordination and interoperability of air, land and sea capabilities, and overlapping operations into the integrated air and missile defense enterprise.”