A while back, someone wanted to see how this lens does when tracking a bird flying AT you. While these aren't brilliant results, I managed a short couple of bursts this weekend and the weakness in the images are not due to the lens:
I'm not the greatest (really, I'm not even moderately *good*) at in-flight shots; if I can pull this off in the short distances that I had to work with, I'd imagine that someone that actually knows how to set up for one could do pretty darned well with it.
They look great. Much to modest!