[freeflight]

> Country A does not fight random country B for no reason.

No, they usually don't. But countries, nations, and people often have very long lasting disagreements. Instrumentalizing those, for another "bigger" cause isn't really that hard of a task for the far more influential and powerful countries C and D.

C and D end up supplying A and B with money, weapons, training and sometimes even direct manpower.

The result is usually a conflict that escalates much more quickly in scope and severity than it would have without the involvement of C and D.