The Hoenn Region holds a plethora of Flying-type Pokémon, but I will only list the ones that can learn the HM Fly: Swellow, Pelipper, Crobat, Dodrio, Skarmory, Altaria, and Salamence. (I am not counting Tropius and Xatu beause they're not very useful)
Swellow
Swellow is a solid choice, with stellar Speed and a decent Attack stat. He's able to learn some strong moves, has a good Ability in Guts and is available very early on. For a moveset, try:
- Fly
- Return/Quick Attack
- U-Turn
- Steel Wing/Roost/Quick Attack
(I'm assuming you don't care about Natures or EVs, but if you do I'll add them)
Pelipper
Another good Pokémon also available early on, Pelipper can function both as a fighter and an HM slave, learning Fly and Surf. He has good HP and Special Attack. Try this moveset:
- Fly
- Surf
- Shock Wave (move tutor)
- Ice Beam/Roost
Crobat
Crobat is an incredible Pokémon with a variety of moves. He also has amazing Speed and useable Attack, as well as powerful STAB attacks. This is a good in-game moveset:
- Cross Poison
- Fly
- X-Scissor/U-Turn
- Steel Wing/Roost
Dodrio
While often overlooked in favour of more powerful Flying-types, Dodrio can hold his own in-game. He gets wicked high Attack and Speed, as well as Fly (don't ask me how). Here's the recommended moveset:
- Fly
- Quick Attack/Return
- Drill Peck/Roost
- Steel Wing
Skarmory
A nice defensive monster to add to your team, although you already have Slowbro. Still, Skarmory is a positive addition to any team with his amazing Defense. Usually a Skarmory would know moves like Defog and Stealth Rock, but since in-game is usually hyper-offensive, I will suggest an appropriate moveset:
- Fly
- Steel Wing/Iron Head (move tutor)
- Rock Slide/Roost
- X-Scissor/Night Slash/Roost
Altaria
Altaria possesses an incredibly diverse movepool, able to run both physical and special movesets. This, when paired with its decent bulk, make it a good choice for a Flying-type to add to your team (that, and it's a freaking cloud dragon).
Physical
- Fly
- Dragon Claw
- Dragon Dance/Roost
- Earthquake
Special
- Fly
- Dragon Pulse
- Moonblast
- Flamethrower/Ice Beam/Roost
(I would recommend using Altaria's Mega Evolution, but it isn't necessary.)
Salamence
And finally, the king of all Hoenn Flying-types, Salamence. He is a literal killing machine (or is that KOing machine?) that tears through all who oppose him...except Ice-types, be sure to have a counter for those.
- Fly
- Dragon Claw/Outrage
- Earthquake/Stone Edge/Rock Slide
- Crunch/Zen Headbutt/Fire Fang
Well, those are all of the viable Flying-types in OR/AS who are not Tropius, Xatu, Rayquaza or part Bug-type. I hope you're able to find one that works for you.