[waynechef]

Flying a wide body to Memphis or Cincinnati requires a lot less fuel than flying across the Atlantic from SAT. You need the added runway length to safely operate the takeoff with all the extra fuel weight, and for the weather variables that occur. Heat, wind and humidity all have a hand in the aircrafts' take off performance level. As far as Data to back this up, I don't have it at hand but I could look it up if you would like. I am going off from what my father had told me several years ago concerning this very issue. He was a 747 pilot for 20 years.