That's odd. My great uncle (born around 1886) used that phrase all the time, and wasn't an aviator or a modeler. He was, however, in the horse cavalry (pre WWI). I think it's a reference to how a horse holds its tail when in a full gallop.

Of course, a deer hunter might think it refers to how a whitetail raises its "flag" when spooked and runs off.

I like the airplane version, too, but the one "balls to the wall" is my particular favorite.