I have a question about the fuel consumption!
So at the moment I am flying a Boing 747. This flight has a flight time of 10 hours. I loaded 18 hours of fuel (don´t ask why) and now I´m on cruise level but only have fuel for 9 hours?
As you burn fuel you will get lighter, which will mean you need less thrust to maintain level flight so your fuel flow will go down. This means you can gain extra time. If you step climb as well you can fly for even longer.