Complex sentence: It was also built by, or exported to, several countries outside of Britain and used by their air forces; in this context, the Hurricane was unusual in that it was flown operationally by both the Allies and the Axis during the war.
Split into simpler sentences: It was also built by, or exported to, several other countries. The Hurricane was unusual in that it was flown operationally by both the Allies and the Axis during the war.