Last weekend I tried for the first time considerable amount of flyers in my list, and the result speaks for itself. Flyers immunity to close combat attacks (i.e. most death stars) and their hard to hit profile made them deadly force in the hands of any capable commander. To add further insult to injury it would seems flyers are best countered with flyers themselves.
It would appears the skies of 41st millennium is going to be filled with angry warplanes until most armies can get their hands on decent AAs.