"If higher tax's are made on avation fuel, this may help the smaller airports"
Smaller airports do not have the throughput to allow them to make the economies of scale which are possible at the larger airports. It's a bit like the supermarkets; the bigger you are, the better deal you can leverage from your suppliers. The issue of aviation fuel is a case in point. Manston doesn't use vast amounts and so, they have to pay top-whack for it. In addition, at Manston, all of the aviation fuel has to be brought down to the airport from Essex in road tankers. If fuel prices rise, they not only have to contend with the rising price of the aviation fuel, but also the rising cost of diesel for the tanker fleet. In essence, a small airport, like Manston, faces a double whammy.
All the talk about cargo tonnages seems a bit glossy to me. What actually matters is not the raw tonnage, but how much money you are making from it. As I recall, Planestation weren't making much out of MK. They tried to increase the fees and MK went to Ostend. MK may be back but I don't know how much Infratil are making from it.