Free of charge, the people who work at the Travellers' Guild provide a Skyrunning service, where they lend you a Pokémon to fly and another to fight with. If you have your own Pokémon capable of learning Fly, you can take it and use it to battle, though the Travellers' Guild will provide one free of charge.
Item Prices:
Poké Ball: $3
Great Ball: $5
Ultra Ball: $7
Avian Ball (designed to work better on Flying-types): $5
Premier Ball: Provided free of charge upon the purchase of 5 Poké Balls simultaneously
Paralyz Heal: $1
Obtainable Pokémon will be decided by a referee. Obtainable Pokémon should either:
1) Be flying type (you cannot obtain Gyarados or any that just cannot be in the air)
2) Have wings
3) Be able to use Fly
Riding Pokémon will not be able to attack, but can be attacked by enemies. You can use your attacking Pokémon to defend the riding Pokémon.
Your Skyrunning adventure will end when:
1) You have no Poké Balls left
2) Either your Riding or Offensive Pokémon has fainted
3) Either your Riding or Offensive Pokémon has become paralysed and is untreatable