The Arctic Challenge Exercise 21 is a Royal Norwegian air force-led, Nordic large-force, live-fly Field Training Exercise hosted by Norway, Sweden and Finland, and focused on joint and combined air operations with NATO allies and partner nations from June 1-18, 2021. Exercises like ACE 21 builds interoperability with allies and partners to demonstrate capability and convey a strong deterrent message. During the exercise, the U.S., allies and partner nations will exercise the ability to plan, execute and evaluate Large Force Employments in a multinational air operation.