I created some in-flight arrows by stretching the native model so it's about 3 times longer. While it might sound odd, this makes the arrows look better in the air, a sort of optical illusion similar to motion-blur. It looks a lot better than the default "brown smudge", and is much easier to see than the standard arrows at high speeds, especially if the FPS is low.
I can send you the ones I did if you want or you can make your own if you are using different arrow models. I strongly recommend it, it makes a group of archers look a lot more impressive.