I don't like this idea. Realistic mode isn't all about decreasing every ingame option you have. Surely you have less health, less accuracy a.s.o, but decreasing the amount of jet/fuel would really just be disabeling the gameplay alot.
As it is now, realistic is really just a customized version of normal(or vice versa), but if you decreased the amount of jet it would be a hole new game. At least if you ask me..
I don't mind changes being done to realistic and normal, but leave jet the way it is.