The plan is simple. Wait for the storm and then fly the supplies dirigible over the enemy city, apparently lost. The grey storm will make it impossible to see from inside the dirigible, so you have to rely on magnetism. As will the enemy. If they don’t shoot you down you just walk into the balloon and fire a few rounds yourself.
You won’t make it out of there alive. You will be captured or killed. If they somehow have the sense not to use the supplies, at least make sure they don’t sever your heads when they kill you.