If your an airline selling tickets today based on $2.00/ gallon jet fuel, you need to be able to hedge against fuel prices rising. If you require delivery, then who will buy the other side of the rising fuel prices bet? It’d have to be another commodity consumer (or a producer or storer), but other airlines and other consumers of oil products aren’t going to get on the other side of this bet, they have to hedge against rising prices (consumers), and on the other side of the bet(producers, storage), I doubt that oil companies would like to take delivery of a bunch of cheap oil. (just what they need when prices are down)
Another problem is if your an airline (again, sorry) say you’ve got a contract with say Chevron to provide you with x amount of fuel for the next year, what happens when you have to take delivery of your contract as well?