Would a de-aerating fuel tank have any benefits?
There are ways of preventing air from being pulled into fuel lines due to change in speed,
direction, or orientation.  On of the simplest is called a "clunk" line, which is a flexible hose with a weighted fuel inlet at the end. The inlet and fuel simply fall to the "lowest" level G forces take it.  

As far as fuel entraining air by agitation, important factors are viscosity and the chemical
make up of the fuel.  Fuel is generally "thinner" than oil so air can escape more easily.
Chemically, fuel does not have the tendency to form bubbles as a mixture of soap and water would.  Air entrainment simply is not an issue with flight maneuvers.  No doubt the oil
companies have a good number of chemists to keep it that way.