From the Super Mario Wiki
Fly is a Flying-type move appearing in every installment of the Pokémon series. In addition to being an attack, players can also use the move to instantly travel to locations they have visited. The move also makes appearances in the Super Smash Bros. series.
Fly is also the up special move of Charizard for its playable appearances in Super Smash Bros. Brawl and Super Smash Bros. for Nintendo 3DS / Wii U. Charizard flies up into the air in a spiral motion, dealing multiple hits to any opponents caught in the attack. In Super Smash Bros. Brawl, Charizard covers itself with fire when flying into the air, while in Super Smash Bros. for Nintendo 3DS / Wii U, this is replaced with wind.
Super Smash Bros. for Nintendo 3DS / Wii U also introduces custom variations for this move:
The first one is Rising Cyclone, which does not give as much vertical distance, but draws in foes, and has greater launching ability.
The second is Fly High, which increases Charizard's flying height, but does not inflict any damage to opponents.