Pokemon Abilities
In "Pokemon Red," Pokemon creatures can develop abilities in two different ways. Some abilities develop naturally as a Pokemon levels up, giving it new attacks or defensive maneuvers as it becomes more powerful. Other abilities are given to a Pokemon using special items; these items can be used only with certain Pokemon types. Items that bestow abilities are typically rare, leaving players to choose which of their eligible Pokemon receive the ability in question.
Charizard
In "Pokemon Red," Charizard is the ultimate evolution of one of the game's three starter Pokemon. If you select the Charmander Pokemon at the beginning of the game, you will have the Pokemon evolve into Charmeleon when it reaches Level 16. If you continue to use Charmeleon during the game, it will evolve into Charizard automatically when it reaches Level 36. By the time the Pokemon evolves into Charizard, you will have chosen four of eight different abilities that the Pokemon receives between levels 1 and 36.
"Fly" Ability
The "Fly" ability serves two purposes in "Pokemon Red." Pokemon that can fly are able to use the ability in battles as an attack, and may also use it on the overworld map to warp to different locations in the game world. In "Pokemon Red," the "Fly" ability must be added to eligible Pokemon using an item; the availability of "Fly" as a naturally evolved ability doesn't occur until later games in the series, starting with "Pokemon Ruby" and "Pokemon Sapphire."
Teaching Charizard to Fly
To teach Charizard to use the "Fly" ability, you must have the "HM02" item that you receive from a woman west of Celadon City. Using the item allows you to select the Pokemon in your active party that you would like to apply the ability to; if you select Charizard, it will be granted the "Fly" ability. If Charizard already has four abilities learned, you will have to discard one of the four in order for it to learn the "Fly" ability.