Roughly 4% per hour of the excess carried. So if you are carrrying 500 kg extra on your 1000 mile flight, 3 rotations a day, and the other 150 aircraft in the fleet are doing the same, for 365 days a year, you are burning around 13,141,000 kg a year (over Thirteen thousand tonnes,) just in tankering the excess fuel alone.
At a price of $1100 per metric tonne, that is $14,455,100 (nearly Fourteen and a half million US Dollars a year.)
Which, given that Mikey-the-Pikey's 'airline' allegedly carried 78.48 million passengers in the 12 months to Aug 2012, to be sure, to be sure, works out at about 11p per passenger.....
