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So Delta has splashed out, and bought an oil refinery, in a move that will be watched closely by all transport companies. Will it be the start of a rash of freight companies entering the oil business? Or will it be a horrible mistake for an airline – already in one of the most challenging industries – to enter a second, equally challenging industry. And the carrier has gone into this business at “the high cost point of the curve”, according to this article from Platts which sheds some light – and doubt – over the hugely ambitious move.