Like their commercial cousins, fighters, reconnaissance planes, helicopters and other military aircraft around the region sat idle for days. They are just now beginning to come back to life, although fighter jets — which have highly sensitive engines — remain grounded across much of Europe.
The Belgians and Finns tested their planes in the ash environment and suffered engine damage for their troubles.
NATO's airborne warning and control aircraft shifted to Italian bases to continue their missions.
The grounding has affected the war effort:
Getting supplies to Afghanistan has also gotten more complicated, and troops have had to deal with mail not being delivered properly and low supplies at base stores.
As I noted, this would have been a big freaking deal if the balloon had gone up in the Cold War, rather than being an inconvenience today.