BarbiesBoyfriend,
If you burn 4% of your 500 kgs per flight, with x flights per day x 365 days per year, the numbers start to add up. So you cant look at one flight and say that its not worth it!
The longest sector that we tanker is 10 hours, we use 40% of the loaded tanker fuel to get it there. But with the cost differential between the two airports, its an excellent way to make money.
Mutt