Why can't my charizard learn fly?

Question

I was playing pokemon red and to my horror my charizard could not learn fly trachy said that was a move for him in the movesets for pokemon red. if he can't learn it in taht game can I have a move that would be good to replace it in the moveset trachy gave me

Comments

What's it's moveset?

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Flamethrower, earthquake, slash, fly

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Sorry. Forgot about that. How about Fire Spin, which pretty much gives you free damage back in Gen 1?

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Huh. The game freak dudes that made pokemon red and blue must have forgot about that or something. No doubt that it pissed off a lot of players. I know I got pissed off.

Answer 1

In generation I,Charizard is unable to learn Fly except in Pokemon Yellow Version. that's the reason your Charizard can't learn Fly