Was struggling with the same problem on a spaceship prototype. Everything was zero or disabled.
Fluid Friction to zero turned it off completely for the spaceship. Far as I understand it’s simulating air friction using the value from DefaultPhysicsVolume in World Settings. Couldn’t find it anywhere as a setting but that does the trick.
Might be related to the Fluid Friction value in Project Settings under Engine - Physics but changing the default friction there had no effect.