We don't know how much fuel was on the plane. There should be only enough for their mission plus some extra amount in case of emergencies.

A jet leaving LA going to Hong Kong is going to have a lot more fuel than the same jet leaving LA going to Texas. Besides the obvious reason that extra fuel is needed for distance, they don't want too much fuel onboard in case of an emergency where they may have to make an emergency landing. That could require either burning off extra fuel before the landing or even dumping it. The military would avoid wasting the money on fuel if at all possible.

I doubt the plane was empty so there still should've been some fire but possibly not a gigantic fireball.