You are kidding aren’t you? I don’t know any airline or for that matter charter company in the world that doesn’t do this to some extent. I know of trucking companies that do this to avoid the higher taxes that are present on diesel in some states compared to others. It is quite right and responsible for any transport company to tanker fuel if they believe they can reduce their operating costs by doing so. If you take your analogy to its conclusion maybe we should stop people filling their petrol tanks up in their cars because you burn more petrol per/km than if you only had the fuel to do a one way trip to work or the shops etc. While we are at it maybe we should make it compulsory by law to car pool to work. The number of cars that I see with only one occupant in them is staggering.