STRATEGYLike all of the other trainers in the Fortree City Gym, Gym Leader Winona specializes in Flying-Type Pokemon. However, Winona doesn't just use Flying Types, she mixes Flying with other types. Through out the games she has Flying mixed with Normal, Steel, Water, and Dragon. Therefore, when battling Winona it is important to use Pokemon that won't be weak against the opposite type. I am going to build a strategy team, not with specific Pokemon, for how to easily win against Winona in Omega Ruby and Alpha Sapphire. She has a total of four Pokemon in her party, and they are as followed:
Swellow, Lvl 33, is the Normal/Flying Type Pokemon that Winona uses in her party. Swellow knows Quick Attack, Aerial Ace, Double Team, and Endeavor. Normal Type Pokemon only have one true weakness and that is Fighting Type, however, they are only immune to Ghost. This allows other Types to be effective, but not super effective. We should not use a Fighting Type because they are weak against Flying Type Pokemon. So, I would suggest using a Fire or Electric Type Pokemon in this scenario. You will want your Pokemon to be high in speed in order to attack first and defeat Swellow quickly.
Pelipper, Lvl 33, is the Water/Flying Type Pokemon that Winona uses in her party. Pelipper knows Water Pulse, Roost, Protect, and Aerial Ace. Water Type Pokemon only have one true threat, and that is Electric Type Pokemon. They can be super effective against Fire, Ground, and Rock Type, so stay away from those types of Pokemon. Although Grass is effective against Water, it is weak against Flying Types. Because Flying Types are also weak against Electric Type Pokemon, I would definitely use that to your advantage and pick an Electric Pokemon. Pelipper may be slower then Swellow because of its weight, but it still has the advantage of flight, so still try to use a Pokemon with speed, especially because Roost can heal it's HP.
Skarmory, Lvl 33, is the Steel/Flying Type Pokemon that Winona uses in her party. Skarmory knows Sand Attack, Air Cutter, Steel Wing, and Aerial Ace. Defensively, Steel types are considered to be one of the best types of Pokemon to use. Steel Types are weak against Ice, Rock, and Fairy Type Pokemon. (Fairy Type won't effect Winona's Skarmory, however, because Fairy doesn't exist in the Hoenn region yet). Super effective Types are Fire, Fighting, and Ground. Therefore, I would use a Fire or Electric Type because Ground has no effect on Flying Types. Steel moves are not very effective against Electric, and Flying are weak against them. Steel Type's usually strive in Attack, so you will definitely want a Pokemon with speed and/or high defense as well.
Altaria, Lvl 33, is the Dragon/Flying Type Pokemon that Winona uses in her party. Altaria knows Earthquake, Dragon Breath, Cotton Guard, and Roost. Dragons are among the most elusive and powerful of all Pokemon. Pokemon that you should not use against Altaria are Fire, Water, Electric or Grass because they aren't very effective at all. However, Dragon Types are extremely weak against Ice, Dragon, and Fairy (Once again, Fairy won't help here because Fairy hasn't been introduced yet). So, the only probably Pokemon to use here is an Ice Type because both Dragon and Flying Types are weak against it. Like Pelipper, Altaria knows Roost, so she can heal herself during battle and and remove the Flying-Type from the Pokemon for that turn. This is okay though because as we discussed, Dragon is also weak against Ice.