ore is heavy so it is not economical Why would you, when we have the great Lakes here to float it around the Rust Belt
Iron ore is heavy but that's not the problem. The demand for iron ore is for large quantities but it's not usually urgent.
Iron ore is heavy, and air freight is charged by the pound. It's more economical to send it via boat or train, which can move heavier products at a fraction of the cost. If time is crucial or the object is important, however (which isn't likely with iron), air might be the way to go regardless of the cost difference. Think about if you need to get iron to a factory on time. If you don't the factory will be shut down for several hours. In that case, it would be cheaper to send it by air, rather than the cost of shutting down the factory. Let's pretend it's not iron we're talking about. The example I just gave does happen (not with iron, that I know of, which is in a nice logistic flow that wouldn't be disrupted by rash decision).That's generally it, though.
