overpitched, the answer is yes. The aircraft has time to overcome inertia in the turn.
As with everything in Physics, many assumptions are made based on magnitudes of seperate effects. In the case of a downwind turn, with the rate of turn slow enough, the problems people encounter are due to maintaining ground reference so the inertial effects are assumed to be neglible. If you could turn fast enough you may be able to see inertial effects.
Try this in flight. On a very calm day with a light helicopter, find the max angle of bank that will allow you to maintain an airspeed (~60kts) in level flight. On a very windy day (without gusts) with the same helicopter, same AUW, same DA, set the same angle of bank and see if your airspeed fluctuates. Good luck finding the right conditions, even if you do I won't guarantee you'll see much, but in this instance the inertial effects may become apparent.
Milt, the rotation of the earth does factor into aviation. That is why when flying in the northern hemisphere there is always a small correction to the left whereas in the southern it's to the right. It's called a coriolis force. Again, this is so small that it's ignored in most discussions.
Matthew.