Well, I just defeated Cynthia in my Flying ultimate! Since my last update, I defeated Team Galactic and Dialga and traveled to Sunyshore city where I defeated Volkner. He wasn't too difficult because he only had two electric types on his team.. After that, I traveled north and through Victory Road to the Pokemon League. I then defeated my rival before taking on Aaron, Bertha, Flint, and Lucian. Of the four, Lucian was the easiest thanks to Honchkrow and the other three were all about equal in difficulty. For Cynthia, her Miloctic posed a bit of a problem, defeating most of my team before succumbing to Staraptor's Return. The rest of her team fell pretty easily until Garchomp. Luckily, it could only use Dragon Rush against Drifblim due to type immunities, so with some carefully timed switching and healing, I was able to whittle down its HP with Staraptor. Luckily, Cynthia used Giga Impact to defeat my Staraptor which left Garchomp recharging while Drifblim was able to come in and defeat it.
Now that I'm finished with that challenge, which I started many moths ago, I'll go ahead and work on completing my Flying run in Black 2!

Staraptor / lv64 / Close Combat, Return, Brave Bird, Aerial Ace

Drifblim / lv62 / Shadow Ball, Fly, Payback, Thunderbolt

Mothim / lv62 / Air Slash, Psychic, Hidden Power (Rock), Bug Buzz

Honchkrow / lv63 / Wing Attack, Night Shade, Night Slash, Dark Pulse