When they do take flight, they are extremely poor flyers (just look at their size - those wings can't carry all that weight for long) and cannot get off the ground very high. Basically, they fly from tree-to-tree and not over long distances.
So, fearing that you will be hit while riding a coaster is a near-impossibilility and unfounded phobia. Sure, you may run into them if your dining in a wooded area of an amusement or even along the midway. But all anyone really has to worry about is the noise (as if that were truly troublesome in the first place).
Closed topic.