I don't know why they have surcharges. Surely if a business's costs/overheads increase they increase the price of the product.
If the increased cost of deisel fuel impacts on the bus company, bus fares go up.Who ever heard of bus fares with a surcharge. Or a surcharge on the Manly Ferry! By persisting with surcharges the airlines are asking for critisism when the public start working out the maths.
Hide it in your fare structure I say.