Harptera

[poweroftibarn]

Pokemon with great design, great stat, great ability, and terrible movepool.
Seriously, why this thing doesn't learn X-Scissor? or even Aerial Ace?

Anyways, Gale Wings is still Gale Wings. It's cool that it can overspeed Scarf Nucleons(if they didn't use quick attack) despite your EVs and nature.
With Choice Band, Wing Attack is enough to finish Nucleon in one hit, so maybe you should consider a Choice Band set based on spamming U-turn, instead of not holding anything and spam Acrobatics.

Forget Talonflame in original game. That bird is ridiculously strong (so ridiculous that I quit battling in original game) because that thing can use Brave Bird AND hold Choice Band/Life Orb/Rocky Helmet/etc.
This thing can't hold a thing if you want to use strong flying attacks, which hurts a lot.
Of course, Wing Attack heavily lacks in power. But think it as a priority move, and now it has 50% more power than Ice Shard/Aqua Jet/Mach Punch!

So, my set would be like:
Harptera@Choice Band
Ability: Gale Wings  
EVs: 252 Atk / 4 Def / 252 Spe  
Jolly Nature
- U-turn
- Wing Attack
- Bug Bite
- Crunch/Brick Break

Make sure you have some good walls behind you:Using this set means many switches by U-turn!
Also another fast sweeper like Nucleon and Yatagaryu is good too, because you can send them in freely if your opponents decided to switch their Pokemon against Harptera, and you choosed U-turn.

Choice Band is pointless on Harptera.  Acrobatics with no item will deal more damage than Banded Wing Attack.  You are much better off just going itemless to increase your power and options.