Machinbird, with your tab on a wing tip light example I'd suggest "imagine a maple seed." They do NOT fall straight down or deflect in breezes the same. The tab makes them "fly" more rather than sink like an avocado. And their spiral is non-trivial.
JD-EE, That was one of the mental examples I used, but I was having trouble rembering what kind of tree produced those seeds.
Guess my forgetter is working very well.
But in water, the rotation rate of a maple seed type airfoil would be severely slowed.